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PROCEEDINGS Second Lie
Hoston Socety of Natural History. SE ek GV ic
1870-1871.
BeOwsuy ON: PRINTED FOR THE SOCIETY. TRUBNER & CO., 60 PATERNOSTER ROW, LONDON. Eee 2.
PUBLISHING COMMITTEE.
T. T. Bouvet. Tuomas M. BREWER. SaAmMuEL LL. ABBOY. A. S. PACKARD, JR.
Epw. BURGESS.
PRESS OF A. A. KINGMAN. MUSEUM OF BOSTON SOCIETY OF NATURAL HISTORY, BERKELEY STREET,
PROCEEDINGS
OF THE
BOSTON SOCIETY OF NATURAL HISTORY.
TAKEN FROM THE SOCIETY’S RECORDS.
Wednesday, June 15, 1870.
Vice President, Dr. C. T. Jackson, in the chair. Forty-eight persons present.
Voted, on motion of Mr. C. J. Sprague, to suspend the rules and make the Report of the Nominating Committee first in the order of proceedings.
Mr. Edward Pickering, in behalf of the Nominating Com- mittee, presented the following report :—
The committee appointed at the last meeting of the Society to nominate a President, have attended to that duty, and beg leave to report. The name which first suggested itself to your Committee was that of our first Vice-President, Charles T. Jackson, one of the earliest, most constant and devoted of the friends of this Society. Upon his unwearying interest in its welfare, his liberal contributions to its treasures, his courtesy as a presiding officer, his well-known scientific attainments, it is not necessary, in the presence of this Society to enlarge. We are all witnesses. But the reception of the following letter has prevented the Committee from offering his name as a candidate tor the office.
PROCEEDINGS B. S. N. H.—VOL. XIV. 1 JUNE, 1871.
Pickering.] 2, [June 15,
Boston, June 13, 1870. Epwarp PickerInG, Esq., Chairman of Committee.
My Dear Sir:
Having been informed that the Committee on Nomination of Pres- ident of the Boston Society of Natural History were disposed to offer my name as a candidate for that office, I beg leave through you to say to the Committee, that however highly I consider the proposed honor, I cannot consent to become a candidate, since my health, which is often impaired, especially in the winter months, might be inadequate to the very important duties and constant atten- tion required of the first officer of the Society. So far as my health and ability will permit, I shall always be happy to labor for the interests of the Society, and whatever influence I can exert will be in its favor.
A younger man than myself, I believe, would be able to serve the Society as President much better than I can, and my personal preference would be in favor of the promotion of the second Vice- President, Mr. T. T. Bouvé, to the Presidency of the Society.
Most cordially thanking the Committee for their favorable con- ’ sideration, I have the honor to be,
Your Obt. Servt. Cuarues T. JACKSON.
I am under these circumstances instructed by the Committee to propose for the office of President of this Society, the name of our second Vice-President, Thomas T. Bouvé.
KE. PickERING, for the Committee.
Boston, June 15, 1870.
It was then moved by Dr. C. F. Winslow that the report be accepted, and that the Society proceed to ballot for the candidate presented by the Nominating Committee.
Dr. J. B. 8. Jackson moved, as an amendment, that the ballot be postponed to a meeting to be held on Wednesday next, of which notice shall be given in the newspapers on the Monday and Tuesday preceding, and on Wednesday, the day of the meeting.
Dr. D. H. Storer moved, as a second amendmcni, that the ballot be postponed to the first meeting in October.
1870.] 3 [Bliss.
The amendments were rejected, and the motion of Dr. Winslow prevailed.
The ballot was ordered. Dr. J. C. White and Mr. B. P. Mann were appointed scruteneers. They announced as the result that thirty-three votes had been cast, thirty-one of which were for Mr. Thomas T. Bouvé, and he was declared elected.
The Secretary read a list of nominations for membership. The following communications were presented : —
ON THE OSTEOLOGY OF THE ANTERIOR VERTEBR&H IN Doras NIGER, WITH A COMPARISON OF THE STRUCTURE OF THE Dorsat Fin in DorAs AND Battistes.! By Ricuarp Buiss, JR.
In the preparation of the present paper I have limited myself to a discussion of the above mentioned subjects, in the hope of being able at some future day to prepare, with appropriate illustrations, a monographic work on the Osteology of the Doradide. Hence the consideration of the osteology of the head, shoulder-girdle, pelvis, etc., has here been omitted.
The tendency of the anterior vertebre to coalesce, so peculiar to the cartilaginous Sturgeons and Plagiostomes, is also manifested in some of the osseus fishes, it being particularly noticeable in Fistularia, Dactylopterus, many Cyprinoids, the Siluroids and allied families.
In Fistularia the four anterior centrums are greatly elongated and anchylosed, their parapophyses unite to form a continuous lateral ridge on each side of the centrums, and the neural spines form a similar ridge above them.
In Dactylopterus the first four centrums are united into a tube sustaining a solid wall above, formed by the union of the neural and interneural spines.
1 Having been engaged in the study of fishes, under the direction of Professor Agassiz, at the Museum of Comparative Zoology, for several years, I have had ample opportunity of studying the different modifications of fin-structure in the various genera of Siluroids and Doroids, the collection brought by Professor Agassiz from Brazil being exceedingly rich in the genera and species of these families, to which valuable material I have had free access during the preparation of this paper.
Bliss.] 4 [June 15,
t
In the Cyprinoids the three anterior centrums are soldered to- gether. The parapophyses arising from them exhibit a modification _ of structure quite remarkable. The coalesced neural spines are much developed, but the interneurals are small, and exhibit no striking peculiarities.
But it isin the Siluroid and its allied family, the Doradidz, that this enlargement of the centrums, and the modification of their apophy- ses and spines is carried to its greatest extent. In these groups the centrums are so firmly united that the sutures are almost obliterated. The neural and interneural spines are often so thoroughly united as to form a solid wall extending from the centrum to the nuchal plates, separating the right and left halves of that portion of the body above the vertebral column. ‘The parapophyses of these soldered vertebree present the most diverse forms, sometimes appearing as porous, rounded prominences, as in Doras niger, at other times uniting and forming a broad shield projecting from the sides of the coalesced centrums, as in Perinampus typus.
Intimately connected with this extraordinary condition of the ver- tebral elements, are the modifications which we observe in the osseous rays of the dorsal fin of these fishes. The lateral apophyses of the interneural spine supporting the first fin rays, not only serve as articulating surfaces for the bases of the rays, as is ordinarily the case, but spread out into dermal plates, which unite together in a sincular manner to form a nuchal shield, to which Cuvier gave the name of “ bouclier.”1
In Doras niger the united anterior vertebrae are four in number, the first three exhibiting modified parapophyses; in the third is seen the first indication of a costal organization.
The first centrum is quite small, and is closely united to the basilar bone by a serrated suture. Its small, thin, neural spine rests anteriorly against the prolonged occipital crest; posteriorly it is united to the first neural spine of the next vertebra, and there rising half way to the shield covering the neck, meets the point of the first interneural spine.
1 For a detailed description of the fin structure in the various families of fishes, I would refer to a series of papers by Dr. Rudolph Kner, ‘‘ Ueber den Flossenbau der Fische,’’ published in the Sitzungsberichte der Kaiserliche Akademie der Wissenschaften Wien, Vols. xi, pp. 807-824. 1860 ; x11, pp. 232-260, 1860; x1, pp. 128-152, 1861; xxiv, pp.49-80, 1861.
1870.] 5 | [Bliss,
‘
This interneural spine, which is small and thin, expands at its upper extremity into a thick, superiorly arched plate which forms a part of the nuchal shield. Anteriorly this plate is united by sutures to the supraoccipital and parietal bones. Posteriorly it is embraced by the two anterior branches of the dermal plate belonging to the second interneural spine. Cuvier, Meckel and others, have described this plate as a lateral expansion of the top of the first interneural spine, affirming that this spine had no corresponding fin ray. This seems to me, however, to be incorrect, for this plate, although in many species closely united to the interneural spine, appears to be, in reality, a modified dermoneural spine —the first spine of the dorsal fin,— thus altered from its normal form to constitute a part of the defensive armor of the neck. An examination of our common Amiurus catus tends to confirm this view; for in that species the homologue of this plate is not soldered to the upper end of the
_interneural spine, but rests loosely upon it; showing that it is a dis-
tinct bone.
This plate, above described, exhibits every variety of form in the different members of the Doras and Siluroid families. In some it is very large, and forms a prominent bone in the nuchal shield. In others, as in Oxydoras, it is a slender, lozenge-shaped piece inter- calated between the supraoccipital and the large plate of the second interneural spine. In many Siluroids it is removed from the cranial bones, uniting only with the supraoccipital at its posterior extremity. This is the case in Perinampus typus. In Amiurus catus we find it reduced to its minimum of development, and hidden under the thick skin of the body.
The second centrum is six times as long as the first, and carries an anterior and posterior pair of parapophyses, not united together at their bases, as is the case in many Siluroids. ‘The anterior pair of these apophyses consist of thin, vertically expanded plates, arising in common from the centrum and the neural spine above, and expand- ing at their extremities into porous spatulate discs, to which the anterior portion of the air bladder is attached. Ordinarily in the Siluroids the extremities of these apophyses are not thus modified, but unite by synarthrosis with the suprascapula. Between the cen- trum and the bases of these apophyses are found, on each side, three small curiously shaped bones united to one another and to the cen- trum by ligaments. Posteriorly these bones afford attachment toa portion of the investing sheath of the air bladder. ‘The anterior
Bliss.] 6 [June 15,
portion of the larger bone passes through an opening im the basi- occipital into the cavity of the cranium. These bones have received the name of “the bones of Weber,” in honor of Weber, who first described them, and who homologized them with the bones of the ear in mammals. Owen, in his “Anatomy of the Vertebrates ” (Vol. I, p. 844, et seq.), shows them to be a part of the auditory apparatus, connecting the acoustic labyrinth with the air bladder. Owen says Weber mistook the relation of analogy for one of homology when he named them malleus, incus, and stapes.?
The posterior pair of parapophyses consist of small and thin trian gular plates rising outward and upward, for a short distance, from the centrum.
In the first centrum of Doras niger the hemapophyses exist as downward prolongations of the centrum, forming a deep furrow in its inferior surface. In the second centrum the furrow is closed for nearly its entire leneth by the union of the hemapophyses. In the third and fourth centrums the hemapophyses form a furrow, as in the first, which exists also in the two following centrums, though much less distinctly marked. Hence the hemapophyses form a continuous furrow on the under surface of the coalesced centrums, but unite in the second so as to form a tube.
The second centrum has not only two pairs of parapophyses, but also two neural spines. The first neural spine of this centrum (the second spine of the vertebral column) starts from the anterior por- tion of the centrum, above the anterior parapophyses, and rising upward and backward, meets the downward prolongation of the second interneural spine, to which it is firmly united. ‘This inter- neural spine has two outstanding lateral wings ; these expand supe- riorly, and uniting form a single broad and arched dermal plate,
1'This view of Weber was strongly opposed by Geoffroy St. Hilaire, who consid- ered these bones to be the modified ribs of the first, second and third vertebrae. Meckel was inclined to agree with Weber in considering them the homologues of the bones of the ear. Saagmans Mulder described the bones as a part of the audi- tory apparatus; believing the air bladder to be identical with the tympanic mem- brane. Later, however, he came to the conclusion that the bones considered by Weber as malleus and incus, were but ribs; and the stapes as transverse apophyses of the first vertebra. Brechet believed them to belong to the auditory apparatus, and Valenciennes considered them as special bones. Baudelot reviews the subject at some length in ‘‘ Comptes Rendus”’ for 1868, pp. 330-334 and comes to the conclu sion that these bones represent the superior arches of the first and second vertebrz the inferior arch of the third, and the os intercrural parted in two.
1870.] 7 (Bliss.
which covers the neck immediately in front of the dorsal fin. The anterior, posterior and lateral margins of this plate are concave, forming a pair of arm-like projections in front and behind. The anterior arms partially clasp the plate, which I consider to be the first dermoneural spine, and unite by suture with the two parictals and with the posterior angles of the suprascapular bones. The pos- terior arms embrace the second dermoneural spine, and are firmly united to the two lateral apophyses of the third interneural spine.
Behind the plate just described rises the second dermoneural spine ; but so modified that its true nature as a fin-ray is not at first discernible. A smooth bony projection or keel rises from the top of the second interneural spine, behind and somewhat beneath the roof formed by the last described dermal plate. This keel, which is somewhat sharply ridged and rounded anteriorly, supports the second dermoneural spine. This spine is a short, triangular, forked bone, anteriorly convex and posteriorly concave. When in posi- tion it rides upon the keeled crest, and is hidden beneath the skin surrounding the fin. Its posterior edges give attachments to liga- ments connecting it with the third dermoneural spine, and a pair of muscles extend from the arms of the rider to the anterior edge of the articulating facet of the third interneural and to a portion of the dermal plate above. From the anterior face of the rider, just above the fork, arise two muscles which are attached to the inner surface of the dermal plate immediately in front of the spine. These two sets of muscles serve to move this spine up and down upon the keel, by which the large spine behind it is raised and lowered as will be described hereafter.
The third neural spine rises above the second pair of para- pophyses belonging to the enlarged centrum, and meets, and is united to the interneural above, in the same manner as is the one before it. It is also united to the neural spines before and behind it. In fact, the neural and interneural spines of the second, third and fourth vertebra are so soldered together as to form a wall almost entirely dividing the space above the vertebre.
The lateral ridges of the third interneural spine expand supe- riorly into two lateral apophyses modified into dermal plates. The anterior edges of these apophvses are united to the posterior arms of the plate in front of them ; posteriorly they extend downward and outwardly, and terminate in an obtuse point.
On each side of the fin the top of this third interneural spine is
Bliss.] 8 : [June 15,
formed into an articulating facet, upon which rest the two lateral branches of the third dermoneural spine, and which are kept in position by a pair of muscles extending from the outer edges of the facet to the posterior edges of the arms of the spine. The bone between the facets is hollowed out for the reception of the down- ward projection of the middle portion of the spine. This spine, the third dermoneural, is very large and thick, and has on its ante- rior edge a row of stout conical teeth. The posterior edge of the spine is furrowed and likewise furnished with teeth, but smaller than those in front. The base of this spine is widened and perforated through its centre in an antero-posterior direction. The head of the interneural beneath is united without suture to the second interneural, and tothe basal portion of the second interneural crest, and projecting backward as a slender, bent rod, passes through the perforation in the base of the fin-spine, and uniting with the interneural again behind the spine, forms a kind of linked joint. I believe that this kind of joint is formed by the inward projection of the arms of the spine through the crest upon the head of the interneural, and not by an antero-posterior prolongation of the crest through the base of the spine. My reasons for this belief will be made evident in my descrip- tion of the first dorsal fin of Balistes, (see p. 10), where it will be seen that though the interneural crest is completely perforated, the arms of the spine do not pass entirely through it. ‘This peculiar mode of articulation is found in the fishing filaments upon the head of. Lophius piscatorius, in which species the spines of the dorsal fin are modified into long filaments to serve a special purpose;! and whose extreme mobility is secured by the kind of articulation I have’ just described. In the ordinary forms of fin spines, the prolongation of the head of the interneural, which passes through the base of the dermoneural spine behind it, does not unite with the mterneural be- longing to the spine through which it passes. But in the Siluroids, as well as in Lophius and Balistes, the use to which the spine is put necessitates this linked-joint mode of articulation. The mechanical operation of this complicated apparatus is as fol-
lows: the enlarged spine of the fin being used as a weapon of of- fense, the union of the neural and interneural spines with each other
1 See, Description des filets pécheurs de la Baudroie, par M. Bailly, Annales des Sciences Naturelles, ler, Ser., Tom. 11, 1824, pp. 323-332; and also, Analogie des Filets Pécheurs, etc., par Geoffrey St. Hilaire, Mémoires du Muséum d’Histoire Naturelle, Tom. x1, 1824, pp. 182-142.
1870.] 9 [Bliss.
and with the dermal plates, serves to give the necessary support to ' the apparatus. When the fish would erect the spine of the fin, the muscles attached to the anterior face of the little forked bone or rider, contract, pulling the bone forward and downward on the rounded crest of its interneural. The articulating facet, upon which rest the arms of the large spine, acting as a fulerum, the ligaments which pass from the posterior edge of the rider to the base of the spine, cause it to rise with the forward and downward movement of the rider. When erect, the spine cannot be lowered by pressure upon it from above; any attempt to thus depress it serves only to pull the rider more closely against the crest which now stands be- tween it and the large spine. By this means the fish is enabled to inflict so severe a wound as to render him a formidable antagonist. In order to lower the spine, the muscles connecting the arms of the rider with the anterior edge of the articulating facet contract, pull- ing the rider up the crest, which, at the same time, allows the large spine to be lowered by appropriate muscles attached to the posterior edge of its arms.
Geoffroy St. Hilaire, in his paper on the analogy of the fishing filaments of Lophius piscatorius with the first rays of the dorsal fin in the Siluroids, published in the Mémoirs du Muséum d’ Histoire Na- turelle (Tom. x1, p. 132), gives a detailed account of this fin appa- ratus, and there shows for the first time, that the little forked bone, which had escaped the notice of former naturalists, is truly a spine of the dorsal fin. He describes it, however, as the first spine of the fin, while, as previously mentioned, I am led to regard it as the second; believing that the dermal plate supported by the first inter- neural is really the first spine.
Cuvier, also, in his ‘ Anatomie Comparée” (Tom. 1, p. 126), al- ludes to this peculiar articulation of the large dorsal spine in the Siluroids ; and in his Valenciennes and * Histoire Naturelle des Pois- sons” (Tom. xiv, pp. 310-322), gives a very brief description of this fin structure in the diagnosis of the family of Siluroids.
The third anchylosed centrum is quite short, not much larger than the first. Its neural spine is broad and short, and unites with the neural spines in front of and behind it, as well as with the inter- neural spine belonging to the first branched ray of the dorsal fin. The parapophyses of this centrum consist of large, porous, rounded excrescences, affording attachments to the posterior portion of the air-bladder. They are true apophyses, and near their bases afford
Bliss.] 10 [June 15,
support to a pair of very stout mbs. A long, and rather thick bone ~ extends from the extremity of each of these ribs to the posterior point of the dermal plate of the third interneural spine. This bone, which is serrated externally, forms one of the series of keeled der- mal scutes which run along the side of the body. It is much larger than the others, and its apparent office is to afford support to the scutes. In Ozydoras, the porous apophyses above described are wanting, though the large ribs are present.
In Doras. the hemapophyses of the third vertebre are not closed beneath the centrum.
The fourth anchylosed centrum is somewhat larger than the third, and differs from it in exhibiting normal parapophyses with ribs of the ordinary form. Its neural spine is united loosely to the neural in front, and to the interneural of the second branched ray. As in the third centrum, the hemapophyses do not unite.
In the Doradide the different members of the coalesced vertebra, and the interneural spines of the dorsal fin are so soldered together and modified, that it is exceedingly difficult to distinguish them. A comparison of Doras with Perinampus typus, however, will aid in determining the relations of the neural and interneural spines in Doras. For in Perinampus the interneural plates are so separated from the bones of the cranium, and the spines themselves so slightly united, that it is quite easy to trace them. But in Perinampus the parapophyses of the coalesced vertebre differ widely from those of Doras, for they are not separate as in this latter species, but unite to form a broad, flat, scale-like bone, projecting laterally from the cen- trums, and bearing, as Meckel has said, a striking resemblance to the carapace of a chelonian.
in connection with the structure of the dorsal fin in Doras, it will be of advantage to make a comparison with the fin apparatus of the first dorsal of Balistes, which, in some points of structure, resembles that of Doras.
In £alistes the apparatus which supports the first dorsal fin con- sists of a number of bones, — the interneurals, — soldered together into a boat-shaped piece which is attached anteriorly by ligaments to the occiput, and supported posteriorly by a bony rod resting against the fourth neural, and the first interneural spine of the second dor- sal fin. This little boat has a deep keel, formed by the union of the two sides. An oval, longitudinal opening in the sides of the boat in its anterior part, affords exit for the two arms of the second spine of
1870.] 11 [Bliss.
the fin. A prolongation of the upper anterior edge of the sides of
the boat extends downward to the keel below the middle of the leneth of tae oval opening. The anterior portion of the keel is somewhat prolonged, and fits into an opening in the occiput, by which additional support is afforded to the apparatus.
This naviculate bone bears three spines; two of them, one imme- diately succeeding the other, are peculiarly articulated with the bone which supports them. The third spine is placed at the hinder ex- tremity of the boat, on a bone, which, though soldered to the bone bearing the two anterior spines, is yet distinct from it, as is shown by the direction of its fibres. A tendon, the use of which will be described presently, extends from the upper part of this third spine to the base of the second.
The first spine is stout and roughened on its anterior face with small, blunt teeth. The posterior face of the spine is deeply grooved, and the two edges of the groove somewhat approach each other to form a kind of shoulder, which, when the spine is erect, rests upon a * projection on the anterior face of the second spine. The portion of the first spine which rests upon the thickened prow of the boat ex- pands on each side, and the bases of these expansions are formed into articulating surfaces, and rest upon corresponding facets on the bone beneath. Between the articulating facets of the naviculate bone, rises a little crest, hollowed so deeply on each side as to form a complete perforation. Into these hollows project two inward prolon- gations of the lateral articulating arms of the spine. But these in- ward prolongations of the arms do not meet through the perforated crest. It is, as will be seen, an approach to the linked joint mode of articulation described in Doras.
The second spine of the fin, which is smaller than the first, is forked at its base, and bestrides a small crest formed by an upward extension of the keel of the boat. The two arms of the spine are prolonged downwardly, as previously stated, through the oval open- ing in the sides of the boat, and are supported movably at the point where the bony rod from the anterior edge of the boat is joined to the keel, below the opening in the side of the boat. The anterior face of the spine is provided with a protuberance just above the fork, upon which rests the shoulder of the large spine in front.
In Balistes, as in Doras, the large spine is used as a weapon, and like that of Doras cannot be lowered till the other spines are’ moved. When the spines are raised the second spine rides forward over its
Bliss. ] 12 [June 15,
crest and fits closely under the shoulder of the large spine in front of it. The third spine is also raised by the tendon connecting it with the second. When erect, any pressure upon the large spine forces its shoulder against the protuberance on the second, which is supported by its crest and by the extremities of its arms, so that a backward movement of either of the spines is impossible, and the large spine is rendered serviceable as a weapon. If now the third spine be pushed down, the tendon which connects it with the second causes this latter to rise and ride over its crest, which thus allows the first spine to be readily depressed by appropriate muscles attached to its base.
The operation of this peculiar apparatus much resembles that of a lock of a gun, and has given to the fish its common name of “ trig- ger” or ‘* cock fish.”’
Thus it is seen that the principle of the working of this apparatus is the same as in Doras, though the means by which it is accom- plished are somewhat different. In Doras it is the third spine which is enlarged to serve as a weapon; while in Balistes it is the first. In Doras the large spine maintains its erect position by pulling the small spine in front of it against its crest. In Doras only two spines compose this weapon, the first of which must be moved before the second can be ; in Balistes three spines enter into the structure of the apparatus; the third to be moved before the position of the other two can be altered. Equal support is obtained in both ; but in the one case resistance results from a pulling movement from behind ; and in the other from a pushing movement from before.1
1 For further information regarding the fin structure of Balistes and allied fam- ilies see Hollard’s Monograph of the Balistide in Annales des Sciences Naturelles, Vol. xx, 38me Ser., p. 101, 1853 ; Meckel’s description of Balistes in his System der Vergleichenden Anatomie, Theil 11, pp. 239-242, 1824; Bruhl’s “ Osteologisches aus dem Pariser Pflanzengarten, p. 58, et seq. and L. Agassiz’ Poissons Fossiles, Tom. II, Pt. 2, p. 249.
1870.] 13 [Packard.
EMBRYOLOGY oF IsoromA, A GENUS oF PopuURIDa&. By A. S. PACKARD, JR., M.D.
*The egos were found laid singly or in masses on the damp under surface of the bark of an apple tree. They are spherical, white, with the chorion very transparent, and measure .0625 of an inch in diame- ter. On the 25th of April many of the young had hatched out; they continued to hatch until the 6th of May.
In none of the eggs was I fortunate enough to observe the segment- ation of the yolk, nor the formation of the blastoderm. Numerous egos, however, were observed, in which the blastoderm had not yet been formed. In these, amid a mass of minute cells, floated four large fat cells, measuring about one-fourth the diameter of the egg itself, with numerous smaller cells measuring about one-fourth the diameter of the largest cells just mentioned. The earliest stage observed was that when the blastoderm has been resolved into the primitive band. (Fig. 1.) At this time the primitive band becomes infolded, indi- cating the cephalic lobes of the head. In a succeeding stage (Fig. 2) the antennal, mandibulary and 1st maxillary segments, and the three thoracic segments are indicated. The formation of the germ thus far closely resembles that of the Phryganeide, as described and figured by Zaddach.
The next change is the closure of the body walls over the yolk, and the appearance of the rudiments of the appendages, and the ceph- alic lobes. At this time, also, the somewhat bilobate end of the abdomen is formed, and also the rudiments of the future ‘“ spring,” consisting of a pair of tubercles, larger at this period than the rudi- mentary antenne. This fact is interesting, as I have observed in other insects (Bombus, Vespa, Cicada, Aschna and Agrion) that these were sternal outgrowths, and not articulated, and therefore, as I supposed, not homologous with the legs and jointed appendages of the head. This spring, therefore, partially represents the ovipositor of the higher insects, the ovipositor originally consisting of three such pairs of tubercles. At this period the “amnion”? or ‘ parietal em- bryonal membrane,’’ appears as a tough membrane surrounding the embryo.
In a succeeding stage the intestine is formed, and the rudiments of the antenne and legs have greatly increased in size. Still later the appendages begin to show traces of articulation, and the
Packard.] 14 {June 15,
tip of the abdomen is deeply cleft by the median furrow of the body. The rudimentary mandibles and 1st maxille are distinct; the ceph- alic lobes appear very distinct, and the antenne are nearly twice as large as the legs. I was unable, after careful and repeated en- deavors, to discover at this or any other period, any traces of the 2d maxille (labium) though they may be found on more careful examin- ation hereafter, as they are present in a very rudimentary form in the adults, and are large and well developed in the Lepismatide.
A later period still (Fig. 3, 38a) is characterized by the differen- tiation of the head as a distinct region of the body; the posterior portion, including the mandibular and 1st maxillary segments, unit- ing with the cephalic lobes, in which the eyes (each now consisting ah eight ocelli) are situated. The antenne are now of much the same shape as in the larva, while the epicranium, clypeus and labrum are differentiated, and the “spring” is fully formed, con- sisting of a pair of finger-shaped, three jointed appendages, the basal joints consolidated into a single tubercle, from which the ex- tremities diverge.
Another well marked stage, 7.e., just previous to the hatching of the embryo, is signalized by the mandibles and 1st maxille becoming acute, closely appressed to one another and to the under side of the head, and withdrawn within the head, so that the mouth is some- what tubular, as it appears in a front view of the head. At this period, also, the absence of any apparent traces of a labium is
worthy of notice.
The embryo throws off the chorion and amnion in a moment, and the larva is very active in its movements. The larva is white, be- coming after a second moult of a purplish hue, while the adults are snuff brown. The larva is much shorter and thicker than the adult, and the spring is very short and stout, while the head is much rounded, and the antenne are short, and thick, and very large. In fact the larva repeats the general form of Podura, Achorutes and Lipura, while the adult is more closely allied to Degeeria. The species, which is undescribed, is named Jsotoma Walkerii, and belongs to Nicolet’s first section of the genus, of which the European J. glacialis is a type.
The development of this insect is throughout very similar to that of the Phryganeide; the germ, as in that neuropterous family, be- ing developed on the outside of the yolk. The parietal membrane —
1870.) 15 (Packard.
was distinct, but the inner or visceral membrane, which exists in the Phryganeidz, was not observed.
Explanation of the Figures.
Fig. 1, egg with the primitive band lying on the outside of the yolk; ab, fold indicating the meeting of the cephalic and abdominal end of the germ; 2, large yolk cells.
Fig. 2, the primitive band, with the rudiments of the cephalic (1, 2, 3) and thoracic (1, 11, 111) segments.
Fig. 3, side, and 3a, front view of the embryo; al, antennz; md, mandibles; mz, maxille; sp, spring.
Knight.] 16 [June 15,
The Rev. C. F. Knight presented to the Society a collec- tion of shells and skulls of various turtles made by him in Florida, during the past winter, and offered some re- marks on the habits of the animals.
He described the construction of the burrow which the Testudo polyphemus [Xerobates Carolinus Agass.] (Gopher) makes, digging a gallery often sixteen feet long, and sinking to the depth of twelve feet, with several chambers branching from it. These are not unfrequently occupied by a curious collection of probably unwel- come guests. On one occasion, a pair of opossums, a raccoon, a rattlesnake more than six feet long, and two other snakes, beside several of the native black rats of the district, were taken from one of these holes. Mr. Knight spoke of the enormous strength of this land tortoise, one of them carrying a full grown man on his back with apparent ease, and of their curious uneasiness if the slightest rain fell upon their thick shells.
The Trionyx ferox [Platypeltis ferox Fitz.] is found in great num- bers in the lakes of middle Florida. It is remarkable as having a leathery integument upon its back and belly, which are only very partially covered with a bony structure, and feet which resemble more the flippers of the sea turtle than the limbs of those found in fresh waters. ‘The anus, in the female, is almost at the extremity of a wide and fleshy tail. The jaws, serrated, and of great strength, are covered with a pendulous upper lip. The nostril is greatly pro- longed, suggesting at first sight the proboscis of an elephant, and it was observed, while the creatures were living in captivity, that they always swam with only the extremity of this nostril exposed above the surface ; while most turtles lift the whole top of the upper shell above the water. This soft shelled creature being a favorite food both of man and various fish-hawks and eagles, it was conjectured that this formation of nostril enabled the creature to keep sub- merged beneath the turbid water and out of sight of its watchful enemies.
Lhe Emys serrata [Trachemys scabra Agass.] in the early summer congregates in great numbers in the shallow parts of certain lakes, and the warm and still bayous near the mouths of those streams which empty into the Gulf. On one occasion the speaker, floating quietly down stream, came upon one of these gatherings where there seemed
1870.] » 17 [Knight.
to be many thousands within the space of two or three acres, cov- ering every log and stump and hummock almost as thickly as shingles lie upon a roof.
The Emys Floridana | Ptychemys concinna es is found in brackish waters near the Gulf. It has upon its fore feet three claws of ordinary length, and two of an enormous development; they being often found nearly three inches long. The reason of this elongation was not apparent, until by close observation from a boat at the mouth of the river Wakulla, the speaker saw two turtles of this species, thrusting these long claws into the holes made by some worm, with which the hard clay bottom of the stream was every- where perforated. The transfixed worms were probably the common food of this turtle.
The Chelonia Mydas (common green turtle) is said by the turtle- fishers to enter the creeks which abound on that coast, and having eaten its fill of the sea-grass growing there, to roll together masses of it, of the size of a man’s head, which it cements with the clay on which the grass grows, and then when the turn of the tide takes it out to sea, follows it, feeding upon it. When, therefore, the fishermen find any of these balls floating down from a creek, they at once spread a strong net across the mouth and almost always secure a number of these turtles.
After referring to the large size of the Loggerhead, Thalassochelys caouana Agass., Mr. Knight called attention to the shell of an exceed- ingly pretty little turtle which inhabits the deep, cold springs of upper Florida, Thyrosternum Pennsylvanicum. When inhabited by the living animal it is covered with a light green, hairy substance; but whether of an animal or vegetable character he could not decide.
Mr. Knight closed his remarks BF saying that this part of Florida, near Tallahassee, with its high clay bluffs and its broad pine plains, was an exceedingly rich field both for the zoologist and the arche- ologist.
Mr. Putnam remarked that Mr. Knight’s communication contained several important and interesting observations on the habits of the several species of turtles on the table, and much that had never been published.
The habits of the young Gopher Cooke Carolinus), as described by Mr. K., were interesting, as showing a marked
PROCEEDINGS B. 8S. N. H.—VOL. XIV. 2 JUNE, 1871.
Putnam.) 18 [October 5,
difference between the habits of the young and old of the same species.
The “green hair” fotieed by Mr. K. as found on the small water turtle (Thyrosternum Pennsylvanicum) was a con- fervoid growth common on the many species of fresh water turtles, -and especially on the members of the family Cinos- ternoidcee and other species living mostly in stagnant water.
The observations on the use of the long nails of the feet of Piychemys he considered as a most important and inter- esting fact added to our knowledge of the habits of turtles, and as another most interesting example of the adaptation of structure to habits.
Mr. B. P. Mann spoke of carbolic acid as a presen He had used two preparations successfully, viz.: Ist, 1 part carbolic acid to 150 parts water. 2d, 1 part canane acid to 57 parts water. Mr. Scudder had informed him that the stronger was the better preparation for the preservation of the larvee of insects.
Prof. N.S. Shaler presented the following papers by title: “On the Progress of Life on the several Continents,” and “On the Geological Structure of the Wachusett Range.”
October 5, 1870.
The President, Mr. Thomas T. Bouvé, in the chair. Twenty- three persons present.
Messrs. Samuel How, Frank D. Millet, Edward S. Shaw and Albert H. Tuttle of Cambridge, Caleb Cook and James H. Emerton of Salem, Daniel T. Letteney and Charles A. Walker of Chelsea, Rev. Caleb D. Bradlee, Prof. Alfred P.
1970.] 19 [Dwight.
Rockwell, C. F. Lyman, Wm. Norton Bullard and Arthur W. Willard of Boston, were elected Resident Members.
Dr. Thomas Dwight, Jr., exhibited some flexible dissections prepared by lim, and made the following remarks on the preservation of anatomical specimens : —
It has always been a great objection to the dried dissections which abound in anatomical museums and are much used for instruction, that they give by no means a true idea of the parts. The branches of the arteries and nerves are there, but their relations to the neigh- boring parts are lost, and the muscles so shrunken as for the most part to be unrecognizable. In short, such preparations are carica- tures, not representations of nature. In May, 1869, I saw in the Musée Orfila, at Paris, some admirable preparations of extremities bearing the label “ Procédé de Brissaud et Lascowski,” in which the muscles, instead of being shrivelled cords, were of natural shape and size, flexible, and in some cases quite red. Motion in the joints was almost perfect, and the arteries and nerves bore their original rela- tions to the other structures.
I declined Dr. Lascowski’s offer to sell me the secret by which they were prepared, and have endeavored to discover it. With the exception of the color, the results have been very satisfactory, as shown by many specimens, some over a yearold. One part of car- bolic acid to five of glycerine preserved the shape and flexibility admirably, but the color was very dark. Perhaps the best prepara- tion is one of a forearm and hand, dissected to show the muscles, arteries and nerves. This was preserved by a mixture made by throwing an excess of two parts chloride of sodium and one of ni- trate of potash, into six parts of glycerine and one of alcohol. This preparation has the disadvantage that there is danger of mould if the specimen be at all exposed to damp, which is not the case when carbolic acid has been used. Preserved specimens of this nature will probably be of great value in the study of Comparative Myology.
In a paper read at the Annual Meeting of the Massachusetts Medi- eal Society, in 1870, I have given a more minute account of the process and of the various mixtures employed.
Dr. J. B. 8. Jackson spoke of the importance, in an educa- tional point of view, of these flexible preparations, and
Winslow:] 20 | [October 5,
thought similar preparations of the internal organs might be made. He doubted if any of these solutions would preserve colors permanently, but if a preparation could be discovered which would preserve the form perfectly, he would be willing to dispense with color.
The following papers were read : —
LETTER FROM Dr. C. F. WINSLOW, CONTAINING A DESCRIPTION oF A Deep EXCAVATION IN THE VALLEY OF THE RHINE, NEAR THE MovuTH oF THE NECKAR, AND OF A MorrTAr- SHAPED PEBBLE FOUND TWENTY-FIVE FEET BELOW THE SURFACE.
HEIDELBERG, BADEN, March 31, 1868.
This afternoon I walked with my friend, Mr. William H. Wahl,! of Philadelphia, a scientific student at the University here, to show him a deep excavation or gravel pit in the flat valley of the Rhine, and give him some idea of the water action by which these valley deposits have been made. The spot which we explored is on the road to Schwetzengen, and is about one mile, or one and one-half miles from the base of the mountain south of the Neckar. The gravel pit is a short distance west of the railroad crossing, and on the. south side of the road, or common highway.
The deposit consists of:
1. Silt, fine and dark yellow, with many helices irregularly inter- spersed, and some small pebbles rounded and angular, extending in irregular, horizontal lines or laminations, with two or three large,
angular, or partially rounded stones, or boulders of granite and red
sandstone, similar to the granite and red sandstone existing in the Neckar valley. (The silt is of the same character as that composing in many places the surface of the valley of the Rhine, and which crops out on the north banks of the Neckar, and which I have ob- served constituting banks of considerable thickness on the flanks of the hill, both north and south of the Neckar valley, and in the Neckar valley east of Heidelberg.) This deposit varies from two to
1 Mr. Wahl soon after graduated at Heidelberg with the first honors of that Uni- versity, and is now (Aug., 1870) a Professor in the Franklin Institute, and an Asso- ciate Editor of the Journal of the Franklin Institute, Philadelphia.
1870.] 21 [ Winslow.
six feet in thickness, according to the irregularity of the surface of the field.
2. Rounded pebbles and stones of all sizes, mixed with some angular ones, composed of granite, red sandstone, muschelkalk, etc., lying in lines or layers at irregular inclinations to each other, as if constantly cut out and disturbed and redeposited by tidal currents of different degrees of strength. Large angular boulders and fine sili- cious sand are here and there interspersed in this gravelly deposit. This varies also from ten to fifteen feet in thickness, with irregular edges of connection with the deposits above and below it.
3. A layer of fine silicious sand fit for mixing with mortar, con- taining few pebbles and presenting a front or outcrop which shows the sand to have been. constantly shifting by the action of wind or water (water without doubt as it appeared tome). ‘This is from one to two and one-half feet in thickness.
4, Another deposit of pebbles, stones, boulders, etc., as described in the second deposit. ‘The excavation reaches down no further than about thirty or thirty five feet from the surface.
We found two German laborers (peasants), at work there in sift- ing this material for mortar sand and building purposes. Perceiving us interested in examining the place and in breaking the stones, they showed us what they called “a curious looking stone,”’ which they had just taken out where the deposit No. 3 joins No. 4. The stone was still saturated with moisture, and looking very dark, as wet red sandstone does look, and sand and small pebbles were still adhering to it as if loosely cemented to it by long contact. I-purchased it of them believing it to be an implement in the domestic economy of some extremely ancient representatives of the human race. The spot where this object was found was twenty five feet from the sur- face of the field as carefully examined and estimated by Mr. Wahl and myself. |
The implement appears to be a red sandstone mortar (like our North American Indian mortars) 3 3-4 inches in diameter, and 1 1-2 in depth, and 3-4 of an inch in the thickness of the shell—or about these dimensions. The object is concave and convex, with rounded edges, smooth and evenly rubbed and worn on the inside like any mortar in long use, and roughish on the outside as if weather worn or knocked about by hard usage. The mark of the pick is visible on the convex part where it was struck when it was dislodged from the deposit in which it was embedded, The laborers informed us that
Hyatt.] 22, [October 5,
some months before they had found a large bone there about eighteen inches long which had been taken by some professor of the University.
Mr. Bouvé thought this object was a natural production, in which opinion other members who examined it concurred.
On REVERSIONS AMONG THE AMMONITES. By Pror. A. Hyart.
In some remarks relating to the origin of characteristics among animals, Mr. Hyatt stated that he had recently discovered a series of reversionary characteristics among the Ammonites which might be considered worthy of exceptional consideration.
These are the peculiar extensions of the pile (ribs so called) and of the intervening sulci, or lateral depressions, across the abdomen or external periphery of the shell, characteristics found especially in Microceras planicosta and laticosta. ‘The genus which was founded upon this peculiarity and the (“ Discoceratide)” Arietide, having been recently subjected to a revision, certain similarities of a very remarkable kind were observed.
It was found, that among the Arietide, Coroniceras rotiforme, occurring in the ‘‘ Bucklandibett ’’ of ‘Oppel, Cor. nodosum, in the upper part of the same bed, Amm. Birchii, just above this in the “ Tuberculatusbett”’ and Asteroceras obtusum, still later in the “Obtu= susbett,” all exhibited toa greater or less degree the planicostan pile on the abdomen during some stage of growth in certain individuals.
In Coroniceras nodosum this is especially remarkable, and the con- trast between the young in those individuals which show this stage, and the adults, with keel channels and septa all so typically arie- tian in character, is very great. In all these species the planicos- tan stage appears only in a limited number of individuals in each species, and is always succeeded in course of growth by the features just described of keel, channels and septa, peculiar to the family of the Arietide. In Ophioceras raricostatum, however, the latest occurring species of the lower Lias which has the typical septa of this family, the planicostan stage is superseded in course of growth only by a keel, this species having no channels.
Of course, in trying to account for the presence of this transient characteristic, one follows the family back to its lowest representa- tives. These may be said to be two species, Caloceras torus and Arnioceras cuneiforme, the former closely allied to Psiloceras psilo-
1870.] 2a (Hyatt.
notum in its septa, and the latter also in its external characteristics. None of the lower forms, however, display, so far as observed, the: planicostan stage, though they occur earlier than the species which do exhibit this peculiarity. The planicostan abdomen, therefore, must either be a new characteristic suddenly interpolated in the erowth of some individuals, or a reversion to certain ancestral char- acteristics which have been discontinued for a time in the lower members of the family.
The lower forms of the Arietide, Caloceras torus and such species as Amm. nodotianum, with which this species is closely allied, have septa that. are similar to those of certain Triassic species, such as Amm. Brunnerit and Amm. Batteni Strachey, which also resemble Psiloceras psilonotum in their septa and forms,
The affinity, therefore, is doubly proved through the latter species, which is a contemporaneous form, and by direct comparison. Besides these there are other species, such as Amm. levidorsatus Hauer, and Clydonites quadrangulus Hauer, which show us that the planicostan abdomen is by no means a new feature. Thus, though we cannot assert that the Arietide are directly traceable to species in the Trias having the planicostan abdomen, we can say that the family on its lower borders have affinities with Triassic species, and that the plam- costan abdomen is found in the Trias. It is probable, therefore, that the same modification, when it occurs in the higher Arietide, after a certain interval of time is a reversionary feature.
The young of Coroniceras nodosum, Amm, Sauzeanus of D’Orbieny, is succeeded in the next bed, the “ Tuberculatusbett,” by a new form, Microderoceras Birchii, whose young are entirely distinct in their mode of development from any of the Arietide, They are at first very cylindrical and smooth, then two rows of tubercles are intro- duced; and sometimes, though rarely, a specimen occurs in which the planicostan abdomen is presented. The septa develop to a more complicated outline in a shorter time than any of the species which follow in the same series or any species among the Arietidx.
Very similar to this in its adult ornaments and septa is Microceras biferum; in fact, I was disposed to think them members of the same genus, until I became aware that a representative species, “ MJicrod. Hebertu,” existed in the middle Lias. This establishes a distinct series for Birchu, and makes it necessary to employ a different name.
1 Haidinger’s Abhand., Bb. 8, p. 23, pl. v, figs. 7-9. Mem. Geol. Survey of India, Stol., vol. v, pl. i, p. 59; pl. v, figs. 2, 8.
Hyatt.] 24 [October 5,
The series which we are now considering, has three other ss allied species in the middle Lias.
The first is Wicroceras laticosta,1 whose young are precisely similar in all respects to Microceras biferum, though the adults differ consider- ably, the planicostan abdomen being brought out more distinctly in the adult stage than in biferum. Associated with this species is Microce- ras crescens, whose septa in the young have the same characteristic outline and proportions as in the adult of Ophioceras raricostatum, though the whole form and external features identify it with MJicro- ceras laticosta. Then there is Microceras arcigerens, whose septa in the young are like those of the compressed form of raricostatum at an earlier age, just before the minor lobes and cells attain a decided prominence.” The whorls in this species are flattened dorso-abdom- inally. The dorsum is broader than the abdomen, and this, together with the flattened aspect of the whorls and the early development of the closely set pil, gives an umbilicus closely simulating that of raricostatum.
The genus Androgynoceras returns to the peculiar pile and tuber- cles of JMicroderoceras Birchii in the adult, though retaining the adult characteristic of Microceras until a late stage of its growth. This is especially remarkable in Androgynoceras hybridum (D’Orb.), but becomes confined to an earlier stage in Androgynoceras appressum.
The next genus of this same genetic series exhibits in Liparoceras indecisum the planicostan abdomen not later than the fourth whorl. In Liparoceras Henley this is apparent at an earlier stage only, and in Liparoceras Bechei it is absent altogether.
The same mode of growth is here returned to, which was first ob- served in Microderoceras Birch; namely, a smooth, round whorl, suc- ceeded immediately by two lines of tubercles or spines, erected upon pile which do not cross the abdomen, except.as fine, distinct linear ridges. ‘The difference between the two species, in other respects, is very great, sufficient, in fact, to constitute very distinct genera. It will be observed that we have here a closed series, one in which the
1In the Bulletin of the Museum of Comparative Zoology, No.5, this species ap- pears under the names of Microceras sinuosum and Microceras maculatum, two species which I now regard as the compressed and gibbous forms of Mic. laticosta.
* This compressed variety is the one figured by Sowerby, and can only be doubt- fully referred to the same species as O. raricostatus, which is much flatter on the abdomen, and altogether different in form as well as smaller, though precisely sim- ilar in the septa.
1870.] 25 [Hyatt.
genetic connection is traceable from species to species, and these species agreeing quite closely, even as regards the two most widely separable forms in the proportions and outline of their septa. The planicostan abdomen is a reversionary feature, occurring transiently and rarely in Microderoceras Birchii, but becoming characteristic of the adult in Microceras biferum, and the prominent peculiarity of the remaining forms of this genus.
That this is not an artificial arrangement may be seen by consult- ing the geological succession of the groups. Microderoceras Birchu is found in the “ Tuberculatusbett” of Oppel. Microceras biferum and Microceras laticostat in the “ Oxynotusbett,” the latter, how- ever, lasting into the middle Lias. In this formation it overlaps Androgynoceras, which appears in the “ Jamesonibett,” followed, and perhaps associated, with Liparoceras Henleyi and Liparoceras Bechei.
Ophioceras raricostatum, with its keel and septa, development and form, allying it closely with the Arietidz, and indicating that its true position is at the head of a series of this family, occupied geologically an earlier position in the “ Raricostatusbett” of the lower Lias, than the two species which resemble it in the middle Lias. These are, undoubtedly, part of the Amm. capricornus of Oppel, and are there- fore found in the “ Davoibett” of that formation.
The planicostan abdomen which occurs occasionally in the young of raricostatum before the keel appears, leads to the conclusion, if we credit the hypothesis of evolution, that Microceras crescens and Mi- croceras arcigerens derived their peculiarities from the same source, and are either directly or indirectly the descendants of this or some other common ancestor. I am disposed to credit the latter supposi- tion. The septa examined were those of young specimens, and in the case of the last named it will be noticed that the resemblance is remarkable in the external features of the shell as well as the septa. No one, however, I am confident, without having subjected them to the closest scrutiny would suspect that they could be separated from Microceras laticosta, with which they are also associated geologically. Again, this species is genetically connected with Microceras biferum on the one side and with Androgynoceras hybridum on the other. According to Quenstedt, the former species is hardly separable in some of its varieties from Ophioceras raricostatum, but if the septa are examined closely they are found to differ, and the young are different.
1 Microceras laticosta here includes also the Amm. capricornus of Oppel and the two species alluded to in the note above, as M. maculatum and M. sinuosum.
Hyatt.] 26 [October 5,
The superior lateral lobes of Microceras biferum always, even in the young, seem to possess a median, minor cell which is absent in O. raricostatum. The latter species is much the largest, and the adult septa differ widely. No genetic connection is traceable in their de- velopment except in very general terms. On the other hand, the affinities of M. biferum in all respects point them out as degraded and dwarfed descendants of Microderoceras Birchii, which precedes them, also, in time.
There are other forms, however, which render these questions still more puzzling. A series of single spined or armatus-like species be- gins with Deroceras planicostatum, Dudressiert and Deroceras ziphius in the “‘Obtususbett,” andis continued by Deroceras confusum in the “ Raricostatusbett.” The development of Deroceras armatum does not join it directly with any of these species, and since it occurs only in the lower bed of the middle Lias it need not be considered in this connection.
Deroceras Dudressieri has the planicostan abdomen in the young, but in the adult possesses the abdomen of Microderoceras Birchii, and in fact differs from that species at this stage principally by the ab- | sence of the inner line of spines; the septa are very similar in both. Deroceras ziphius differs more widely from Microderoceras Birchi than Deroceras Dudressieri, but in features which it is not important to discuss here. Then we have Deroceras planicosia, which never parts with the typical planicostan abdomen, though in the adult it acquires a single row of spines, as in Deroceras Dudressieri; and lastly, Deroceras confusum (Amm. Lohbergensis Emerson), which differs somewhat from D. planicosta in the septa, but more in the slighter form of the whorl.
If, now, we examine closely the development of the septa in Micro- deroceras Birchii, we find that it equally resembles the development of the septa in all of the members of the two series just described, which exhibit the planicostan abdomen largely in their growth. The septa of Microderoceras Birchii on the first quarter of the third whorl acquires three minor cells, and the superior lateral lobes become divided, first by the rise of minor cells from the sides of the superior lateral cells. During the same stage a very minute crenu- lation becomes developed from the side of the inferior lateral cell; this, however, does not increase as fast as its opposing cell, which eventually reaches a very large size, equally dividing the superior lateral lobes.
1870.] 27 (Hyatt.
In Deroceras Dudressieri this process is repeated at about the same period, but the dividing cell does not reach a similar prominence, nor do the septa in general terms become quite as complicated as those of the adult Microderoceras Birchii until a much later period. Thus, while the lobes and cells of the former have become almost as com- plicated as in the adult, on the last quarter of the fourth whorl, those of Deroceras Dudressiert are a full volution later in reaching the same stage, and are never so deeply cut or foliaceous even in the adult as in the adult of Microderoceras Birchi.
The first stage in the development of the latter corresponds to one which occurs in a precisely similar manner in Deroceras planicosta, but not until that species nearly reaches the completion of its fourth whorl. In Deroceras confusum there is no constancy in the de- velopment of the minor cells. Two opposing cells may be brought out unequally, as in the young Birchi, or symmetrically, or only one, invariably that from the side of the superior lateral cell. In other words, the adults have all the modes of division found in the different stages of growth of Birchii, according to the stage at which arrest of development has occurred. In neither Deroceras planicosta or Deroceras confusum do the septa reach a stage of complication com- parable with any but the youthful stages of Deroceras Dudressiert and Deroceras Birchi. D. ziphius was not examined, but the septa prob- ably accord with the growth of the external ornaments and pile which place it near D. Dudressieri. The condition of D. Dudressieri and D. ziphius in the adult stage corresponds in their single external line of spines and rounded abdomen to the early stage of M. Birchii, before the internal line of spines is brought out; that of the adults of Deroceras planicosta and D. confusum to the young of these two species when the spines are developed, and the abdomens still have the planicostan folds. This characteristic, it will be remembered, occurs also in some specimens of Microderoceras Birchii, but is only faintly expressed ; in Deroceras Dudressiert and Deroceras ziphius it is constantly expressed in the young, to a later period in the former than in the latter, and is of constant adult value in Deroceras plani- costa and Deroceras confusum. ‘The inference seems to be unavoid- able that the species of this series, which occur later in time and are all smaller than Microderoceras Birchit, are really dwarfed and de- graded descendants of this comprehensive species.
Considering the septa in the next series, we have first Microce- ras biferum. ‘The superior lateral lobes in this species constantly
Hyatt.] 28 [October 5,
divided equally, as in the adult of Microderoceras Birchu; the supe- rior lateral cells are divided into two unequal portions by a large minor cell, and are very similar in outline to the young of Deroceras Dudressieri on the fifth whorl, and to the young of Microderoceras Birchii at an earlier period, while the cells are broader and less deeply cut than they were observed to be upon the latter part of the fourth whorl. The young of MV. laticosta are precisely similar to the young and adult of Microceras biferum, but the septa bring out equally the opposing median cells, and the superior lateral lobes thus become unequally divided. In the adults they reach a state of com- plication comparable to those of Microderoceras Birchit and Deroceras Dudressiert. With Microceras laticosta are associated the strongly reversionary species, which only need a keel to be classified with the Arietide. This is’ especially the case with Microceras arcigerens, whose septa, in one specimen, are remarkably similar in proportions and outline to those of Asteroceras obtusum, and what is still more remarkable in this same specimen, a slightly raised siphonal line is plainly apparent between the prominent planicostan folds. +
In Androgynoceras hybridum an equally complicated state of the septa is reached at an early stage, and still earlier in the succeeding species of Liparoceras.
Microceras biferum is of small size, about an inch in diameter, and at the latest stage assumes a double row of spines, or is smoother; the pila in all cases closely simulating those of the adult Microderoceras Birchvi at this period. Thus it may be said to play the same part that Deroceras Dudressieri does in the armatoid or single spined series in its external characteristics and form, while in its septa it corresponds to Deroceras planicosta. In the same way Deroceras laticosta may or may not have the double row of spines, but never has a single row,? and never in the adult returns to the rounded abdomen and peculiar pile and ornaments of Microderoceras Birchit. Androgynoceras, however, does return to this condition in the adult, but at the same time another tendency is developed both in
1A close comparison with Zieten Amm. Turneri, which I regard as a variety of Asteroceras obtusum, shows, however, that a discrepancy exists in the proportions of the abdominal lobe and in the remaining general characteristics of form, which do not permit any attempt to trace a direct genetic connection.
2 Microceras biferum occasionally has a broad projection on the pile which might be mistaken for a single spine, whereas it is really formed by the coalescing or arrested development of two rows.
1870.] 29 _ (Hyatt.
the form and septa. One is a greater degree of involution, the outer whorls as they grow, beginning to spread laterally over the sides of the inner whorls, and the septa keeping pace with the increased breadth of the sides, adding to the number of the auxiliary or inner lobes and cells. This higher degree of complication is carried to its greatest development in Liparoceras ; which, however, in its highest species, Liparoceras Bechei, returns wholly to the mode of growth originally observed in Microderoceras Birchii. It proceeds directly from the young, smooth, round-abdomened stage, to produce the double row of tubercles, without the interpolation of the planicostan characteristics. It may be possible that the planicostan stage occurs in some individuals, but this would only complete the parallel with Birchui which sometimes faintly expresses this reversionary feature.
The conclusion with reference to this series appears to be, that its members are also at first deeraded descendants of Birchii, but instead of steadily decreasing in size and ceasing to exist, they first decrease and then speedily increase in size again, adding new elements of complication to the mode of involution, and increasing the number of the lobes and cells. All my attempts to trace a direct connection with those members of the Psiloceratide and Arietidz, which approximate to these series, have signally failed. The planicostan abdomen and the similar septa and forms which are found in the adults of Psiloceras, Caloceras,} and Ophioceras, and in Microceras and Deroceras can be viewed merely as reversions, indicating, as in the different breeds of pigeons, only a common ancestry.
It should be observed also, that where reversion is apparently piled upon reversion, as for instance, in the return of the Birchean characteristics in Androgynoceras, after an interval caused by the pre- potent development of the planicostan abdomen, and an interval of time also, that this is not a reversion at all. It is, in fact, the re- sumption of a normal tendency beneficial to the race, which for a time has been entirely suppressed by the prepotent influence of a true reversionary feature.
This can be doubly proved. In the Deroceran series, where no tendency to increased complication or size is observable, the race becomes enfeebled and dies out almost immediately. In the Microce- ran series, where a constant effort is observable to retain the double
1 A new genus, of which Caloceras torus and tortilis are types.
Hyatt.] 30 [October 5,
row of spines, to complicate the septa and increase the size, the law of acceleration is brought into full play, and overcoming the tend- ency of the species to be arrested in development both of size and characteristics, counteracts this tendency and reproduces the usual or natural succession of forms and characteristics.
This may be substantiated in any series of Ammonites. By com- paring the lower forms with the higher of the same series it will be found that in most instances, when the series is complete, the spe- cies, as in Androgynoceras and Liparoceras, increase the extent of the involution and the number of lobes. This is precisely what occurs in the Arietidz#, which are even more successful in suppress- ing the reversionary planicostan tendencies than the Microceran series.
In this family the higher forms, Asteroceras stellare, Asteroceras ac- celeratum 1 and others, are much more involuted than any of the lower forms, and this is still more strongly expressed in their descendants, the Amaltheoide and Hildoceratide of the middle and upper Lias.
It may be objected that Microceras biferum is a young form of which we do not yet know the adult. Its size, the limited number of the whorls and the likeness of the septa, in the full grown speci- men, to the young of Deroceras Dudressieri and Microderoceras Birchu might be considered as proof of this supposition. The development is just intermediate between that of laticosta and Birchiu; any larger forms could therefore only intensify this relation.
Besides the negative evidence, however, that no large specimens have ever been found, there is something positive.
The possession of prominent tubercles makes it probable that quite an advanced stage of life is reached, since at a corresponding age in laticosta no spines are yet developed.
Similar doubts with regard to the size of planicosta and confusum in the Deroceran series are answered with more difficulty. The grad- ual decrease in size which the series makes from Microderoceras Birchit through D. Dudressieri, D. ziphius and D. planicosta to D. confusum, in all the dimensions of its whorls, when the full sized shells are considered, and the fact that these species, especially D. planicosta, have been very extensively collected, appear to make it probable that we now know the shells as they occurred in the localities and strata in which they are found. That they may be dwarfed speci-
1 New species, which has the abdomen like Aster obtusus, but is more involute than any other species of Arietes.
errr se cer err
1870.] 3 [Hyatt.
mens which did not develop beyond periods corresponding to the
_ younger stages of lower species appears to be very probable.
-
Quite a strong confirmation of this tendency of Birchu to have dwarfish descendants is to be found in its own series, if we may so call the only species which succeeds it and inherits all of its peculiar characteristics. JZicroderoceras Hebertu Opp.1 of the middle Lias is precisely similar to M. Birchi in all its characteristics, except the smaller size of the spines and the shorter diameter of the full grown shell. The superior lateral lobes are not invariably equally divided by a median minor cell, as in D’Orbigny’s figure of this species, but sometimes are unequally divided, this cell being thrown to one side as in Hebert. We know that Muicroceras Hebertii is very much smaller than Mficroderoceras Birchi, because the shell enters upon the old age or senile period of growth before the latter has attained its fullest adult condition.2, The whorls themselves do not differ in size, so that the shell compares with Birchii in the same manner that bife- yum or Deroceras Dudressiert compares with it, and in the same manner that planicosta and D. confusum or laticosta compare with these two; they are as large as the young of the species which they resemble in many cases in their whorls, the only difference being that they do not have as many whorls, or attempt to develop the septa beyond a certain youthful or immature condition. They may be said to be arrested in development so far as size is concerned, and retro- gressive in development when the reversionary characteristics are considered.
Darwin’s close and exhaustive work upon the reversionary charac-
teristics of domesticated breeds is, to a certain extent, unsatisfactory,
since, while it points to a probable ancestor, it cannot, from the na- ture of existing animals, show the preéxisting steps by which the change has been accomplished. The element of time, also, is com- paratively short, and the whole evidence is necessarily hypothetical.
In the cases given above, however, it will be noticed that while the facts are not so numerous and conclusive as in the great pigeon argument, they possess the additional confirmation derived from the consideration of the manner of their introduction and their serial succession in geological time.
1 This is the Amm. brevispina D’Orbigny (not Sowerby).
2 Tt should have been mentioned that D. Dudressteri begins its old age period on the eighth whorl, while still very much smaller than the adult MW. Birchit. -
Hyatt] 32 _ [October 5,
It will be noticed that these reversionary species! all descend from one, to which they may be traced by all the evidences within the scope of observation, and that this single ancestor has occasionally in its own development, characteristics which do not occur in its own series in any of the faune of the lower Lias below its own level, and between it and the Trias. Ke
The objection will naturally suggest itself, that perhaps Mdicrodero- ceras Birchii is a migratory species from India, or somewhere out of Eastern Europe, and that in its native haunts we shall probably find the missing links which connect it with the Trias, and farther find that these have the same reversionary features in their growths. But it must be remembered that the planicostan abdomen occurs in some individuals only, a fact very strongly in favor of the supposition that it is a reversion. Darwin’s observations seem to establish the fact, that reversions are transient characteristics, and peculiarities directly inherited are, on the other hand, more or less constant, ap- pearing in every individual of the species. Farther, the Arietes are a group native to Eastern Europe, during the Lias, and they most unquestionably revert just as the young of Microderoceras Birchii, and in precisely the same transient manner, to the planicostan abdo- men,—or rather, as it ought to be called, the Triassic abdomen, in allusion to the age from which it is derived.
LIPAROCERATIDZ.
MICRODEROCERAS.
>)
Microderoceras Birchii.
Amm. Birchii Sow., Min. Conch., vol. m1, p. 121, pl. 267.
This well known species has septa which are different from those of the so-called Amm. brevispina of D’Orbigny. A perfect specimen of the French brevispina possessed by the Museum is a much smaller shell than the M. Birchu, having fewer whorls and entering upon the old age period, whilst the typical Birchit is still in its prime. In the young the tubercles and pile of brevispina are just as prominent during the younger stages of growth as in Birchii, but in the adult the spines and pile are less prominent, though the latter are more closely set upon the sides of the whorls. The septa, according to
1 And I might add other species, which are not necessary to the present argu- ment. i
1870.] 33 {Hyatt.
D’Orbieny’s figures, differ more from Birchii than they do from Amm. muticus, a true armatoid species, though I think this difference, per- haps, is less than it appears to be from D’Orbigny’s figures. MM. Birchu has two series of forms, as is usual among the Ammonites, one a thick gibbous form, and the other thinner. Brevispina is therefore a different species, a stunted or dwarf descendant of Birchi.
The young of M. Birchi are round, smooth shells, like Thysanoce- ras fimbriatum, marked by prominent lines of growth which represent transient mouths and finally pile. They increase very gradually in size, and acquire a line of genicular tubercles on the fourth whorl, which augment rapidly in size and prominence. On the first quarter of the fifth or last of the fourth whorl an internal line of tubercles appears. ‘These increase very slowly in prominence, until they equal those of the outside line. Occasionally the pile become bifurcated, and sometimes they cross the abdomen, producing a very faint resem- blance to planicosta. This last, however, is very faintly and very seldom expressed, and then at a comparatively late period of the srowth, so that Birch cannot be said to closely resemble D. Du- dressier? in this respect.
The septa on the first quarter of the third whorl acquire three mi- nor cells on superior lateral cells, and the superior lateral lobes be- come divided by the rise of a minor cell from the side of the superior lateral cell. On the last quarter of the fourth whorl these have al- ready become equally divided by the increase of this cell, and the lobes and cells possess much of the adult complication, though the lobes are no deeper than the abdominal lobe. From this it may be seen that the progress in complication is very rapid. Since on the third whorl even the septa have already become nearly as compli- cated as those of planicosta at a very much later period, and on the fourth whorl are very similar to those of D. Dudressiert on the sixth
‘whorl. And onthe early part of the fourth whorl, when the superior
ANaterals become equally divided, they must be very similar to those of the adult M. biferum, and in fact cannot do otherwise than closely resemble them. Sometimes the young have broad tubercles with the pilz: split into two or three parts as in subarmatus, etc.
Microderoceras Hebertii. Amm. brevispina D’ Orb., Terr. Jurass., Ceph. p. 272, pl. 79. ‘¢. Hebert Opp., der Jura, p. 278. |
PROCEEDINGS B. 8S. N. H.—VOL. XIV. 3 SJUNE, 1871.
Hyatt.] a4 [October 5,
The Amum. brevispina figured by Sowerby, appears to be a different species from this, one that shows more prominently the planicostan pile. In fact, Sowerby’s figure resembles closer what I have called Microceras sinuosum (laticosta Sow.) than anything else. These distinctions, and the geological gap which divides the two species, induced Oppel to give it a new name.
MICROCERAS.
Microceras biferum.
Turrillites Valdani D’Orb., Terr. Jurass. Ceph., pl. 42, figs. 1, 3.
Amm. bifer bispinosus Quenstedt, der Jura, p. 104, pl. 13, figs. 10, 11 and 13. :
Amm. polymorphus miztus Quenstedt, der Jura, p. 128, pl. 15, fig. 12.
M. biferum Hyatt, Bull. Mus. Comp. Zool., no. 5, p. 80.
This species has septa very distinct from those of D. confusum, and they approximate more closely in their outlines perhaps to those of Psiloceras psilonotum than to Caloceras torus or Ophioceras raricos- tatum. ‘This is due to the presence of a median cell in the superior lateral lobes in both pstlonotum and confusum, and the outlines of the lobes and cells which are very similar also. The species is of small size and may be readily distinguished from ‘O. raricostatum, with which Quenstedt thinks it to be very closely allied. ‘The young are not so cylindrical as the young or adults of raricostatum, and above all they are never flattened dorso-abdominally with bulging sides, as in the typical O. raricostatum. In fact, the abdomen in the young is con- siderably more elevated, the whole shell being thicker and larger in the young as well as in the adult, than Ophioc. raricostatum at the same age or the representative species, D. confusum. Subsequently, in many individuals, a much closer external similarity is brought about, and this is especially remarkable when the planicostan variety of the young raricostatum is compared with the adult of biferum.
When fully developed, the species may or may not have two rows of spines,as the pila may extend into one large, undivided projection which cannot be called a spine, but is only a prominent, truncated pilum, with or without very slight points or spines at either extremity.
Quenstedt remarks that these tuberculated varieties, when unsym- metrical, correspond to D’Orbigny’s Turrillites Valdani. Another variety presents only smooth pile, and these when unsymmetrical are, according to Quenstedt, identical with Turr. Coynarti of D’ Orbigny.
| | : | : | | :
1870.] 35 [Hyatt.
This unsymmetrical form is less common than in D. confusum, at least in the collection I have examined; and I have never found such specimens as are mentioned by Quenstedt, which, though unsymmetrical in the young, become symmetrical in course of growth. Most of the specimens that I have yet seen have this tendency to form a spiral, expressed on or towards the right side,—remembering that the external periphery is the abdomen and not the dorsum as is gen- erally supposed—on the same side, in fact, as the want of symmetry so frequent in the lobes of Psil. psilonotum.
Though this species has been placed in the same genus as M. confusum, I think it can only be considered as one of a different series of planicostan forms, those with two lines of lateral tubercles.
Variety mixtum.
The two specimens of this so called species, if the label from the Museum of Stuttgard is reliable, agree very closely with the fig- ure of Amm. polymorphus quoted above, and in their septa with M. biferum of the same age, as well as with some of the other figures of Amm. Polymorphus given by Quenstedt. It may be a variety of that species. One specimen has the Turrillite deformity so often found in MW. biferum.
Microceras laticosta.
Microceras laticosta Sow., Min. Conch., vol. vi, p. 106, pl. 556, fig. 1.
“¢ brevispina Sow., oy * Hh CF eh 2 “ sinuosum Hyatt, Bull. Mus. Comp. Zoology, no. 5, p. 82.
_ & maculatum Hyatt, Op. cit., p. 82.
The young of this species resembles Microceras biferum so closely in all its characteristics, that 1¢ does not differ so much from it, as the different varieties of that species do among themselves. The form of the whorl in most individuals begins very soon to exhibit a flatness of the abdomen and sides and a sharp bending forward of the pile on the abdomen, which are the only distinctive characteristics. The septa are not precisely similar. The differences, however, increase with age as the septa become more complicated and the pile more prominent. Two rows of tubercles are acquired in some specimens during the adult stage. The abdomen is still deeply sinuous as in the typical MW. biferum.
There are two forms of this species, one flatter and less robust than the other, which I have called MZ. maculatum. This has no spines, at least none are apparent upon the casts.
In variety sinuosum, the age at which the tubercles are assumed
Hyatt. ] 36 [October 5,
varies exceedingly, as well as the size and prominence of these and the pile upon which they stand.
There seems to be one constant difference between this species and M. biferum. The superior lateral lobes are unequally divided into three minor lobes instead of, as in M. biferum, being equally divided | into two. The young septa are precisely similar in development, and also similar to those of the adult and young of Deroceras plan- | icosta ; the superior lateral lobes being at first equally divided by a cell arising from the side of the superior lateral cell. This is sub- sequently met by a cell advancing from the other side and making | the usual threefold division of the lobe.
Microceras crescens.
M. crescens Hyatt, Bull. Mus. Comp.'Zoology, no. 5, p. 82.
In this species we have a form which is intermediate between I. laticosta and Ophioceras raricostatum. It agrees with the latter in its septa, and with M. laticosta in its pile and general external char- teristics of form and growth. In one specimen from Rautenberg, © there is a Turrillite distortion, but the deviation of form is in this case very marked toward the left instead of the usual dextral twisting. The superior lateral cells are broad and very slightly indented by the minor, divided into two unequal portions, however, by one minor lobe slightly larger than the rest. The superior lateral lobes are equally divided, the inferior laterals very shallow. All the cells are very broad in comparison to the lobes. The superior lateral lobes are about two-thirds as long as the abdominal lobe, and the inferior not more than half as long as the superior lateral.
Microceras arcigerens.
Amm. arcigerens Phill., Geol. York, p. 163, pl. 13, fig. 9.
M. arcigerens Hyatt, Bull. Mus. Comp. Zool., no. 5, p. 82.
In this species the septa are very peculiar. The outlines are remarkably simple. All the lobes are remarkably broad, the supe- rior laterals and abdominal nearly of the same height, and the infe- rior laterals fully two-thirds as long as the superior laterals. The whorl is compressed abdomino-dorsally, and much broader on the dorsal than abdominal side. This, and the prominence of the closely set pile in the young, gives the shell a very decided resemblance to O. raricostatum. It will be observed that in this ease the resemblances to O. raricostatum are in those very external characteristics in which none could be traced in M. crescens.
1870.] 37 (Hyatt.
DEROCERAS.
Deroceras Dudressieri.
Amm. Dudressiert D’Orb., Terr. Jurass., Ceph., p. 325, pl. 103.
From France, this species comes to us with the name of Amm. brevispina, and from England, as Amm. armatus or Birchii. With none of these except Amm. armatus has it any close affinities. From Amm. armatus it differs in the septa, besides having very different young. The shell is strongly pilated and tuberculated and has the planicostan abdomen very distinctly marked, whereas Deroceras armatus does not repeat this last feature so decidedly, being much more cylindrical and smoother. The pile are also closer together in Deroceras Dudressieri, the spines and pile also being filled with solid, shelly matter, instead of the spines alone, as in D. armatus. Oppel has stated that he found Amm. Dudressieri of D’Orbigny in the Eng- lish lower Lias, and this species is so closely similar in all respects to D’Orbigny’s figure of this species, that it seems to be the only one he could have seen. D.confusum comes so near to the young of this species that in external characteristics they seem to be nearly iden- tical.
The young is smooth for the first four whorls; the pile begin on the fifth, but the tubercles are hardly visible until the last half of the sixth. Soon after the pile begin to appear, first as folds on the sides, they stretch across the abdomen and form the planicos- tan flexures. Though there are some slight differences between the young of this species, on the fifth and earlier half of the sixth whorl, and the typical planicosta, both in the shell and septa, they are hardly sufficient to distinguish the two forms separated from the adult whorls. On the seventh whorl the spines are very large but decrease in prominence on the eighth, the pila approximating more. The abdomen also becomes more elevated and rotund instead of rather flat- tish, and the whole form approaches closely to what it is in Birchit. The first three whorls have sides widely divergent ; these become rounded on the fourth, flattened on the fifth and sixth, divergent on the seventh, and rounded on the eighth. On the latter part of the tenth whorl the tubercles entirely disappear, the pile being reduced to mere folds. The period at which these characteristics may be obtained or
1 From this I of course exclude the form figured by Quenstedt as having a keel in _ the young.
Hyatt.] 38 [October 5,
parted with, is subject to considerable variation, sometimes an entire whorl earlier or later.
Deroceras ziphius.
Amm. ziphius Ziet. Verst. Wurt., p. 6, “sp 5, fiz. 2
D. ziphius Hyatt, Bull. Mus. Comp. Zool., no. 5, p. 81.
This species occupies a position precisely inten elite between | D. confusum, D. Dudressieri and the true armatoid, large, single- | spined species like the typical armatus. It has, in the young, an abdomen similar to the planicostan abdomen observed in the two first named species, and in the adult it drops this characteristic for an abdomen similar to that found in D. Dudressieri, assuming at the same time a row of large single tubercles. My observations were made upon a single specimen, but they are confirmed by Quenstedt | who takes a similar view of the relations of this species from more extended experience.
Deroceras planicosta Hyatt.
Amm. planicosta Sow., Min. Conch., vol. 1, p. 167, pl. 73.
Microceras planicosta Hyatt, Bull. Mus. Comp. Zoology, no. 5, p- 80.
For the first four whorls this species is smooth, and the wheels is remarkably broad, with gibbous sides. On the fifth whorl the pile are introduced as depressed folds, and gradually increase in size. Spines are never developed in the majority of the specimens, but in a few cases they may be noticed rising either on the cast or the shell, during the third quarter of the sixth volution and becoming quite prominent on the last quarter. The number of pile on a single whorl, the time at which they cross the abdomen, and the pres- ence or absence of tubercles, vary remarkably. The abdomens of some specimens may be crenulated by the first pile, or they may re- main smooth even throughout the fifth whorl, and the number of pile vary from twenty in some to twenty-six in others.
The septa also in the young, instead of retaining the usual propor- tions of the superior lateral cells and lobes, almost obliterate these two which are represented, as in the adult of Coroniceras tenue, by a row of minor lobes and cells. It, however, still retains the peculiar median cells of the superior lateral lobes, which are so characteristic of the three series of planicostan forms. These begin to show them- selves as lateral expansions or crenulations of the superior lateral cells on the latter part of the fourth or early part of the fifth whorls. The subsequent division of the superior lateral cell into two unequal por-
1870.] 89 (Hyatt.
tions by a pointed minor lobe, the depth of the superior lateral lobes about equal to the abdominal lobe, and the shallowness of the inferior lateral lobes, together with the great breadth of the cells and sim- plicity of outline of the cells, and absence of numerous minor lobes and cells, are all characteristics of the Arietide.
They show that planicosta, and the series to which it belongs, come nearest to this family ; in fact, are precisely intermediate between the Microceran series and the Arietide. If, indeed, specimens of D. con- fusum sometimes have a keel as stated by Quenstedt, the evidence is still stronger. In the adult the triplicate division of the base of the superior lateral cells, and the outlines of the septa, remind us forcibly of Caloceras torus, the lowest of the Arietide, though the shallowness of the inferior lateral lobes still remains. This, however, is probably sometimes found in C. torus and in those specimens in which the development of the pile is retarded, an external similarity to the smooth abdomen and fold-like lateral pile of C. torus is also produced.
Deroceras confusum.
Amm. confusus Quenstedt, der Jura, p. 127, pl. 75, fig. 89.
‘¢ —_ planicosta Sow., (pars) Min. Conch., vol. rv, p. 149, pl. 406, not 73.
Microceras confusum Hyatt, Bull. Mus. Comp. Zoology, no. 5, p- 80.
Amm. Lohbergensis Emerson, Die Liasmulde von Markoldendorf, pe Gli iple3) fig. 8. .\)
In this species the first three and a half whorls are smooth and flattened ventrally, the sides bulging as in O. raricostatum. This resemblance is still further increased by the development of the pile. On the latter part of the fourth, fifth and sixth whorls the resemblance to raricostatum is very close, or rather to the earlier stages of that species before the keel appears. On the sixth whorl the tubercles begin to appear and the form changes ta a more laterally compressed and thinner whorl, and the tuberculated pile cross the abdomen as in the typical planicosta.
The septa on the fifth whorl are quite like those of raricostatum in their outlines, though the inferior auxiliary lobes and cells slope inwardly and posteriorly. All the shells examined were small, hardly more than an inch in diameter. ‘The developmental resem- blance to Q. raricqstatum does not extend to the septa. These have a close similarity to those of Caloceras torus, differing however in one
Hyatt.) 40 [October 5;
essential point,—the presence of median minor cells which equally divide the superior lateral lobes. This characteristic, though it may be absent in many specimens, is so constant that it prevents the direct connection of the young of this species with the young of C. torus or O. raricostatum, which it otherwise so closely imitates.
The resemblance to the young of JMJicroderoceras Birchii is not so close, however, in external features, though the septa are very closely allied. The Turrillite variety is quite common in this species, - whereas it is not so common in the true Amm. planicosta Sow.
One of Quenstedt’s figures of this species represents a young shell decidedly keeled. This, I think, cannot be of the same species, and his accompanying descriptions do not justify its associations with his Amm. Bronnit. .
The variations in the lobes are excessive. The median cells of the superior lateral lobes are usually largely developed, often, though not invariably, retaining the youthful or one-sided aspect which they have in the young of Deroceras planicosta and M. Birchii. In some specimens, however, they are very small, and the lobes are unequally divided by two very minute minor cells. These lobes, in other words, may be equally divided, or have all the gradations from this to a state of unequal division. The same lobes are either longer, equal to, or shorter than the abdominal lobe, but seem invariably to greatly ex- ceed the inferior lateral lobes.
Deroceras densinodum.
Amm. armatus densinodus Quenstedt, der Jura, p. 105, pl. 13,_ fies. 9, 10.
D. densinodum Hyatt, Bull. Mus. Comp. Zool., no. 5, p. 84.
This species does not apparently occur in the middle Lias as stated in my paper in the Bulletin of the Museum of Comparative Zoology, but only in the lower Lias. The mistake resulted from an erroneous reading of the label on the specimen. It may be only a variety of D. confusum, but the young differ somewhat, the abdomen is nar- rower and the septa are invisible in the single specimen of D. densi- nodum in the possession of the Museum.
According to Quenstedt’s figure this species is really an armatus in which the young is pilated or ribbed at a very early period, instead of being smooth as in armatus proper. Having only the young it is impossible to say much about the affinities of the shell ; it is, how- ever, evidently a member of the planicostan group or series of Deroceras.
1870.] | 41 [Hyatt.
ANDROGYNOCERAS.
From the specific descriptions it will be seen that we have here two groups or series, both developing from the first variety of one species, Androgynoceras hybridum. From this we have the series in which acceleration of development produces the flattened abdomens and broad whorls of the second variety of A. hybridum, and of Liparoceras indecisum, the more elevated, though still broad whorled adult of LZ. Henleyiy with young just like the adults of A. hybridum, second variety, and finally the high whorled Z. Bechei. The amount of involution is just proportionate to this progress, reaching to the first line of tubercles in the first three forms, to the second only in the adults of the fourth, and to the second in both the young and adults of the fifth.
The second offshoot or series contains only one species, A. appressum, which is highly accelerated when compared with A. hybridum. 'This has remarkably flattened sides and the connection with the other is shown by the development of the young. Whether this ought to be set aside as a distinct genus, or not, will depend upon the discovery of other descendants.
Androgynoceras hybridum.
Amm. hybrida D’ Orb., Terr. Jurass. Ceph., p. 285, pl. 85. ©
And. hybridum Hyatt, Bull. Mus. Comp. Zool., no. 5, p. 83.
For six volutions the shell is apparently inseparable from certain forms of M. laticosta. Upon the seventh whorl, instead of continuing the same degree of increase in size, a more rapid enlargement takes place, the lateral pile become less prominent and more crowded, sometimes coalescing near the umbilicus. The inner tubercles in the latter case, also, either partially or entirely coalesce. ‘The abdomen in the meantime has become more prominent, less furrowed, and more rounded, and the sides converge outwardly. The abdominal pile split up each into several minor ridges on the latter part of the seventh whorl, reducing these furrows to a minimum.
A variety of this species from Schippenstadt and Semur completes the same stages of growth as have been described in A. hybri- dum, a full volution earlier. It has at the end of the sixth volution a whorl nearly as large and of the same form, but much broader in pro- portion to the length than in the first. The pile begin to take upon themselves similar characteristics. J am unable to state whether this or some intermediate form between this and the first variety is the
Hyatt.] 42 [October 5,
one described by D’Orbigny ; or with any certainty, whether the first variety is a distinct species, though it seems to be such.
Androgynoceras appressum.
And. appressum Hyatt, Bull. Mus. Comp. Zool., no. 5, p. 83.
For perhaps the first four or five volutions the shell is similar to the young of thinner varieties of MJ. laticosta. The extent of envelopment, also, is slight ; soon however, on the last of the fifth or first of the sixth the planicostan pile split into several ridges united at either end by tubercles. The abdomen at this period, the inclina- tions of the sides, etc., closely resemble the characteristics of the adult of the first variety of A. hybridum.
LIPAROCERAS.
Liparoceras indecisum.
Lip. indecisum Hyatt, Bull. Mus. Comp. Zool., no. 5, p. 8.
This is evidently a very much more accelerated form than even the second variety of A. hybridum. It still preserves, however, the form of the adult of this species. The young, if I am correct in referring a young specimen from Rautenberg to this species, has plan- icostan pile certainly until after the completion of the fourth, and probably until near the end of the fifth volution.
Liparoceras Henleyi.
Amm. Henleyi Sow., Min. Conch., vol. 11, p. 161, pl. 172.
Naut. striatus Rein, Naut. et argo., p. 85, pl. 8, figs. 65, 66.
L. Henleyi Hyatt, Bull. Mus. Comp. Zool., no. 5. p. 84.
This species differs from the last in not repeating the planicostan abdomen at all, unless upon a volution preceding the last quarter of the third. This seems improbable, though it may occur in some speci- mens. At this period in the specimens examined all the adult char- acteristics were well developed, and it only remained for them to increase in size. ‘The form of the shell is also precisely that of the adult A. hybridum, second variety, or at least of that shell at. the end of the sixth volution.
The L£. Henleyi differs from LZ. Bechet in having larger and more prominent tubercles, a broader whorl in proportion to the height, and in the slighter involution of the young. For the first four whorls the involution does not reach the internal line of tubercles, leaving a larger umbilicus than in Z. Bechet. In one specimen from Lyme Regis the only distinction from Bechei consists in this single
1870.] 43 [Hyatt.
characteristic. Usually, however, the angular, prominent, ribbed tubercles of the younger whorls at once show great differences. While LZ. Henleyi thus seems to show variations advancing towards L. Bechei, the last never has a variety like L. Henleyi. Liparoceras Bechei. Amm. Bechei Sow., Min. Conch., v. 111, p. 143, pl. 280. Ke Ziet. Verst. Wurt., p. 37, pl. 28, fig. 4
Lip. Bechet Hyatt, Bull. Mus. Comp. Zool., no. 5, pl. 84.
Fold-like lines of growth are prominent in the young, which are otherwise smooth and rounded. ‘These increase in number and sharpness until they become true pile.
Two lines of tubercles are introduced, also, in the young, but appear either quite late or comparatively early on the third whorl.
The septa on this volution precisely resemble the septa of the nearly adult JZ. laticosta. ‘They have very broad abdominal and superior lateral lobes; the latter unequally divided. The siphonal cells are very large. In one specimen a very decided resemblance to A. sternalis is produced by the angulation of the abdomen and the unusual development, for so young specimens, of the lateral pile with their tubercles on the last quarter of the third whorl.
Section of Microscopy. October 12, 1870. Mr. E. Bicknell in the chair. Fifteen members present.
Mr. C. Stodder exhibited a slide containing albumen coagu- lated with carbolic acid, which had been carefully sealed in July, 1869. With a high power, he showed that the particles were in continual vibration. He thought the appearance of this preparation was identical with what was represented in figures published by Dr: Lionel 8. Beale, in his germ-theory of disease.
Dr. C. Ellis remarked, that all such particles from their mi- nuteness, appeared alike; and that any solid in a state of fine . subdivision exhibited this molecular motion. Their motion was no proof that they were alive.
Bicknell. ] 44 [October 12,
The following paper was presented :—
A Mernuop oF PRODUCING VERY LOW POWERS FOR THE Microscorgs. By Epwin BICKNELL.
I use a plano-convex “collecting,” or “ reducing” lens, in the draw tube of the microscope, about midway between the objective and eye- piece; it is achromatic, of four inches focal length and six-tenths of an inch in diameter. | A
Placed about midway between the objective and eyepiece, its effect is to reduce: the magnifying power of any objective about one-half; at the same time shortening the “working distance” of the objective materially. Used with a 2-inch, 3-inch, or 4-inch objective it practi- cally makes them 4-inch, 6-inch, or 8-inch, respectively. Its effect is not good with high powers, where of course it is not needed.
By using a similar lens as an objective, in connection with the reducing lens, I have a very low power of only five or six diameters and three and a half inches working distance. This power takes into the field of the lowest eyepiece an object, eighty-eight hundredths of an inch in diameter, with a depth of focus of nearly halfan inch.
This lowest power I have found very useful in viewing whole flowers, large sections, Zoophytes in glass troughs, etc., as all their parts, both breadth and depth, were brought into view at once. i do not bring this forward as an “ optically ” perfect instrument, but as a conven- ient method of producing very low powers for certain purposes. Below I give a table of diameters with the different eyepieces.
Lowest 38-inch. power. objective. Eyepiece Al 2) ro) diameters: 10 diameters. ee Bist teaes SeonO & 18 ee s Coote ce 1S Ge 32
Tt will be seen that the lowest power gives only the magnifying power of the eyepieces used, and the 3-inch only about double the power. ue
1870.} 45 [Hunt,
Wednesday, October 19, 1870.
The President in the chair. Forty-two persons present.
The following papers were presented : —
On THE GEOLOGY OF THE VICINITY OF Boston. By Dr. T. STERRY Hunt.
During the past week I have made several geological excursions in the neighborhood of Boston, in some of which I was accompanied by Prof. N. 8. Shaler, and in the others by Prof. Alpheus Hyatt; the familiarity of these gentlemen with the local geology has greatly facilitated my examinations. ‘The rocks which we have seen may be considered in three classes. A, the crystalline stratified rocks; B, the eruptive granites; C, the unaltered slates, sandstones and conglomerates. The former of these may be separated lithologically into two divisions; the first being the quartzo-feldspathic rocks. Among these are included the felsite-porphyrites of Lynn, Saugus and Marblehead, with their associated non-porphyritic and jasper-like varieties, the compact feldspar of Hitchcock, who has well described these rocks in the Geology of Massachusetts, pages 664, 667. Asso- ciated with them is a granular quartzo-feldspathic rock which is often itself porphyritic, with feldspar crystals, and sometimes appears as a fine grained syenitic or gneissoid rock, often distinctly stratified. This has been described by Hitchcock as intermediate between por- phyry and syenite; his syenites with “a nearly or quite compact feld- spar base”? and some of his porphyritic syenites (Geol. Mass., pp. 668, 669) will probably be found to belong to these granular eurites, which I connect with the porphyries. ‘These rocks are seen inti- mately associated with the porphyry on Marblehead Neck, also in Marblehead, and underlying the argillites of Braintree and Weymouth.
The second division of the rocks of class A includes a series of dioritic and ‘chloritic rocks, generally greenish in color, sometimes schistose, and frequently amygdaloidal. ‘They often contain epidote, quartz, and calcite, and occasionally actinolite, amianthus, scaly chlorite, and copper pyrites. ‘This series holds a bed of dolomite at Stoneham, and serpentine in Lynnfield, where bedded serpentines, dipping at a high angle to the N. W., occur apparently in the strike of these dioritic and epidotic rocks, which include the greenstones of
Hunt.] 46 [October 19,
Dr. Hitchcock, described by him as occasionally schistose and pass- ing into hornblende slate, (Geol. Mass., pp. 548, 647) ; and also his varioloid wacke, under which name he describes the green and choc- olate-colored amygdaloidal epidotic and chloritic rocks of Brighton, and the somewhat similar rocks of Saugus, which are seen within a few hundred feet to the northwest of the limit of the red jaspery pe- trosilex. This series of magnesian rocks is apparently identical with that which occurs with dolomite and massive dark colored serpen- tines in the city of Newport, R. I., where the beds have also a high dip to the northwest. A similar series of strata is largely displayed on the islands and along the shores of Passamaquoddy Bay. ‘The dioritic and chloritic beds towards their base are there interstratified with red felsite-porphyries like those of this vicinity, which, asso- ciated with granular eurites, form great masses in that region. I regard these two types of rocks as forming parts of one ancient crys- talline series, which is largely developed in the vicinity of Boston, and may be traced at intervals from Newport to the Bay of Fundy, and beyond. ‘To this same series I refer the great range of gneissic and dioritic rocks with serpentines, chloritic, taleose and epidotic schists which stretches through western New England.
These ancient rocks are in various places penetrated by intrusive granites, which are generally more or less hornblendic—the syenites of Hitchcock and others. They often contain true feldspars, as in the well-marked granite of Newport, which there cuts the greenish dio- ritic and sometimes amygdaloidal rocks. In this vicinity, besides the granites of Cape Ann and of Quincy, which probably belong to this class, examples of intrusive granites (or syenites) are well seen in Stoneham and in Marblehead, where they cut the greenish chloritic rocks, and on Marblehead Neck, where they are erupted among the felsite-porphyries. In all of these places the phenomena of disrup- tion and enclosure of fragments of the broken rock in the granite are well seen, the lines of contact being always sharp and well-defined. Considerable varieties in the colors and the constitution of these erupted rocks are observed in different localities, and sometimes even in portions of the same mass. ‘This is well seen on Marblehead Neck, where the aspect is such as might result from the simultaneous gushing forth of two somewhat different varieties of granite, as if from contiguous beds of an older granitic gneiss beneath. In one case at Marblehead the eruptive granite is traversed by segregated or endo- genous veins of red orthoclase with quartz and epidote.
1870.] AT [Hunt.
The evidences of the eruptive origin of the granites of our vicinity were well described by Hitchcock, though, as before remarked, he includes with them, under the common name of syenite, many rocks belonging to class A. The coarse white granites on Marblehead Neck are seen in one place intersecting thin bedded and somewhat contorted quartzites, which hold dark micaceous layers, and resemble rather a fine grained gneiss.1_ These beds, which occupy but a small area, are not unlike the strata which at Biddeford, Maine, and in some parts of Nova Scotia, are cut by granites, and probably belong to a newer series than the rocks of class A, as above described. All of these rocks, the granites included, are on Marblehead Neck trav- ersed by dykes of intrusive greenstone, which are sometimes very similar in aspect to certain of the bedded diorites of A.
Of the rocks of class C, the unaltered argillites of Braintree, hold- ing a primordial fauna, were observed by Prof. Shaler and myself to rest directly upon a hard porphyritic felsite of the ancient series. The line of demarkation between this and the soft argillite is very distinct. A more detailed examination than we were able to make during a violent rain-storm, will be required to show whether the contact here observed is due to original deposition or to a subsequent dislocation. Reddish granulites directly underlie the black argillites of Weymouth, and the quartzites with conglomerates and argillites of Chestnut Hill Reservoir, and of Brighton near by, are in several places observed in contact with the old dioritic and epidotic rocks already noticed. The Roxbury conglomerate was observed to contain pebbles of the felsite-porphyries, diorites and intrusive gran- ites of the older series, besides, as already remarked by Hitchcock, fragments of argillaceous slate. In this connection may be noticed a remarkable recomposed rock long since correctly described by the same careful observer, as an aggregate of broken-up and recemented felsite-porphyry, (Geol. Mass., pp. 547, 665). He observed it at Hingham and Cohasset, and Mr. Hyatt has since found it on Mar- blehead Neck, resting directly on the parent rock, and very firmly cemented. The unequal weathering of the surface, however, clearly shows both its conglomerate character and the inferior hardness of the cement. Such conglomerates may of course be of very different ages, a remarkable example of a similar reconstructed telsite-por-
1 These micaceous and gneissic rocks have since been found by Mr. Hyatt to be largely exposed at Naugus Head in Marblehead, where they run to the west of north and are nearly vertical.
Hunt. 48 [October 19,
phyry adjoining the old porphyries of Passamaquoddy Bay, is inter- stratified with fossiliferous sandstones which show it to be of Silurian age. The same thing is observed in Cobscook Bay, near to Eastport, in Maine; while elsewhere similar conglomerates are met with of Lower Carboniferous age.
The fact that the primordial strata of Braintree have suffered no metamorphism is the more significant, since the beds of similar age in New Brunswick and Newfoundland ! rest uncomformably on erys- talline strata supposed to’ belong to the same ancient series that underlies the Braintree beds, and are, like these, unaltered sand and mud rocks. The alteration in the paleozoic strata along our north- eastern coast is apparently confined to the proximity of intrusive rocks. Thus the so-called flinty slates at Nahant, containing patches and bands of epidotic matter, are, as long since pointed out by Hitchcock, penetrated by great masses of eruptive greenstone, and I have found that at distances of a few yards from this they appear as argillites but little indurated. The Upper Silurian beds about Passamaquoddy Bay are, in like manner, altered in the immediate vicinity of eruptive greenstones, becoming hard, greenish and epi- dotic, but the same beds a few feet distant are eee and earthy in their aspect. 7
The difficulties which have attended the study of the geology of this region have arisen in part from great lithological diversities, which led our early observers to separate into different classes rocks of the same geological series; while on the other hand, rocks geog- nostically very unlike were brought together. These points are shown in what we have cited from Hitchcock with regard to the syenite and greenstone, under both of which heads he has placed with true eruptive rocks others which are doubtless stratified. The indigenous greenstones or diorites were at the same time separated
from the amygdaloids and serpentines (which were correctly looked . |
upon as stratified rocks), a misconception which could only lead to confusion. I have ventured in these remarks to state briefly the conclusions to which a few days of observation have led me with regard to the relations of some of the rocks of this vicinity. ‘They will be found, I think, to show a greater simplicity than has hitherto been supposed in the geological structure of the region, and are pre-
1 Mr. Billings informs me that he regards the Paradoxides Bennetti (Salter) from Newfoundland as identical with the Paradoxides Harlani (Greene) from Braintree.
” 1870.) 49 [Dall.
sented, imperfect as they must needs be, in the hope that they may lead some of the members of this Society to give more attention to this very interesting subject of study.
PRELIMINARY SKETCH OF A NATURAL ARRANGEMENT OF THE OrpER DocoGciossa. By W. H. DAL.
The following is a preliminary sketch of a more natural arrange- ment of the mollusca, contained in the Orders Cervicobranchiata and Cyclobranchiata of Gray, taken from the results of investigations now in preparation for publication in a more extended form. These in- vestigations having shown that no line can be drawn between the two orders of Gray above mentioned, it follows that they must be consol- idated; and for the group in question, the Order Docoglossa Troschel (minus the Polyplacophora and Solenoconche), has been restricted and adopted. As the denominations previously applied, all imply an erroneous idea of the structure of the animals, this course has been determined upon in preference to using prior, but incorrect, ordinal names. -
The order, as here restricted, was first recognized by me in ‘ A Revision of the Mollusca of Massachusetts ”’ (Proc. Boston Soc. Nat. Hist., x11, p. 245, March, 1870) at which time only the characters of the suborder Abranchiata had been fully worked out. Since that time I have investigated the characters of the suborder Proteobranchi- ata, as here restricted ; and in a paper read before the American Association for the advancement of Science, at Troy, September, 1870, of which a synopsis was published in the American Naturalist, (November, 1870, p. 561,) I restricted the order Docoglossa within its present limits, from the researches above mentioned. Among the fruits of these investigations was the definite exclusion of the Gadin- tide from the order. (See Am. Journ. Conch., Weis Ooty MUS 0)c . / 1h is proper to state that Prof. Theodore Gill had, upon general con- siderations, adopted the same limits for the order in his unpublished
-Imanuscript, although the conclusions to which I have been led were
«
the result of independent anatomical investigations upon my part, which, so far as I am aware, are the only ones, including the whole order, which have been made. I am indebted to Prof. Gill for sug- gesting the very appropriate names by which I have designated the suborders as restricted.
PROCEEDINGS B. S. N. H.—VOL. XIV. 4 JUNE, 1871.
Dall.] 50 [October 19,
Clas GASTEROPODA.
Order DOCOGLOSSA Dall ex Trosch. 1870.
Suborder ABRANCHIATA (Gill) Dall. 1870.
Radula furnished with a rhachidian tooth and two aaeaae Ani- mal destitute of eyes, branchiz, and lateral teeth on the area.
Family LEPETID# (Gray) Dall. 1869.
Shell patelliform; apex erect, or anteriorly directed. Muzzle of the animal with an entire edge; furnished with a tentacular append- age below on each side.
Formula of the radula, =
Genus Lepeta Dall ex Gray. 1869.
A. Lepeta Dall.
Rhachidian tooth tricuspid, concave in front; central cusp simple, much the largest; lateral cusps small, emarginate, base very broad; uncini with simple cusps.
Type Lepeta ceca (Gray) Dall, Am. Journ. Conch., v, p. 141, 1869.
B. Cryptobranchia Dall ex Midd. 1869.
Rhachidian tooth with three short cusps, equal and parallel before and behind; not pointed. Base moderately broad, more or less ornate behind; uncini with simple cusps.
Type Cr untobranenes concentrica (Midd.) Dall, Am. Sine. Conch., V, p- 143, 1869.
C. Pilidium Dall ex Forbes. 1869.
Rhachidian tooth tricuspid, central cusp much the largest, convex in front; lateral cusps simply pointed; base narrow. Uneini with cusps obliquely twisted.
Type Pilidium fuluum (Forbes) Dall, Am. Journ. Conch., y, p. 146, 1869.
1870.] 51 (Dall.
Suborder PROTEOBRANCHIATA Dall. 1870.
Animal provided with three lateral teeth, with eyes and with ex- ternal branchiz. Jhachidian tooth usually wanting. Uncini pres- ent or absent. '
Family ACM z1D Carpenter.
Shell patelliform; animal provided with a free cervical branchia, issuing from the left side of the body, above the head; muzzle sur- rounded with a frill of integument. Radula without a rhachidian tooth and with three lateral teeth on each side; with or without ac- cessory uncini.
A. Destitute of a branchial cordon. Acmea.
1. Acmea Eschscholtz, 1828. Syn., Tectwre Cuvier, 1830; Tec- tura Gray, 1847. Teeth subequal, parallel in both axes; uncini absent; muzzle
frill produced into two lappets.
0 Formula, W210i 0210"
Type A. mitra Esch., Zool. Atlas, v, p. 18, no. 1. 1833. Philippi. Zeit. f. mal., p. 106, 1846. 2. Collisella! Dall, n. sube. (a). Third lateral smaller than, and opposed to, the second. First laterals anterior. Muzzle frill without lappets. A single minute uncinus on the pleura.
Formula, pel Type Acmea pelta Esch., 1. c. no. 5. 1838. (b). Provided with two minute uncini on the pleura. (? Col- lisellina). Formula, yc Type Patella saccharina Lin., Gmel., 8. N., p. 3695, no. 19. 1792.
B. Cordon present; interrupted in front. Lottia.
1, Lottia (Gray) Cpr., 1863. Without muzzle lappets. Teeth as in Collisella (a).
6 Formula, Tecticpr
1 From Collis, a mound, in allusion to their shape.
Dall.) 52 —_ 19,
Type L. gigantea (Gray) Cpr., Am. Journ. Conch., m1, p. 342. 1866.
C. Cordon present; complete, uninterrupted. Scurria.
1. Scurria Gray, 1847. No muzzle lappets. Teeth as in the last.
0 Formula, 1 @=ar=eyan Types S. scurra (Lesson) Gray, P. L. S., 1847, p. 158. S. mesoleuca (Mke.) Cpr., Maz. Cat., p. 208, no. 263 (as
Acmea). 1857.
Family PATELLID# H. & A. Adams.
Animal without a cervical gill or muzzle frill. Rhachidian tooth rarely present; uncini three in number. A more or less complete cordon of branchize between the mantle edge and foot.
A. Branchial cordon complete. a. Provided with a rhachidian tooth. Ancistromesus.1
1. Ancistromesus Dall, n.¢. Two inner laterals on each side anterior to the third, which is larger and denticulate. Branchial lamellae produced, arborescent. Sides of foot smooth.
1 Formula, SLPS"
Type Ancistromesus mexicanus Dall ex Brod. & Sby. (as Pa- tella) Zool. Journ., tv, p. 369. Rve. Conch. Ic., Patella, pl. 1, nol.) 1855.
6. Without a rhachidian tooth. Patella.
ld. Patella Lin., 1757. Lateral teeth and foot essentially as in the : last. Branchial lamelle linguiform, short, subequal all
around. 0 Formula, SacpILys" Type Patella vulgata Lin., Syst. Nat., Ed. 12, p. 1258, no.
(doen Gil
1From Ayk.oteov, a hook or tooth, and weoos, median or middle.
1870.] 53 , [Dall.
2. Patinella? Dall, n. subg. First inner lateral on each side an- terior to the other two. Second laterals largest, denticu- late. Foot with a scalloped frill, interrupted only in front. Branchiez as in Patella.
0 Formula ; 3@-11-2)3 °
Type Patinella magellanica Gmel. (as Patella) Syst. Nat. 1, p. 37038, no. 52. 1792.
3. WNacella Schum,, 1817. Shell thin, pellucid, apex anterior. Foot frilled, as in Patinella. Teeth bidentate, arranged as’ in the last. Branchial lamelle very small in front, but not interrupted.
Formula, 8(g-44-2)3°
Type Nacella mytilina Gmel., Syst., Nat., vol. 1, p. 3698, no. 28, 1792 (as Patella) = Nacella mytiloides Schum., 1817, and Patella cymbularia Lam., 1819.
B. Branchial cordon interrupted in front. Helcion.
1.. Helcion Montf, 1810. Shell solid, capuloid, with pectinated ribs. Teeth? Type Helcion pectinatus (as Patella pectinata) Lin., Gmel., Syst. Nat., p. ovl0, no, 93. 1792. _ 2. Helcioniscus? Dall, n. subg. prov. Shell depressed, solid, with a subcentral apex. Teeth arranged as in Patinella. Sides of foot smooth. ? = Type Helcioniscus rota (Chemn.) Rve. (as Patella) Conch. ieon. pl. x vit, fis. 39, a, b, c. 3. Patina (Leach) Gray, 1840. Shell very thin, pellucid. Sides of foot smooth. Third pair of laterals posterior, largest, denticulated.
Formula
0
2-13
Type Paiina pellucida Lin., Syst. Nat., X11, 1260, no. 770 (as Patella). 1767.
Formula, Te DES
1 From patina, a dish. 2 Diminutive of Helcion.
Dall.] o4 [October 19,
Soft parts?
1 Metoptoma Phillips, 1836. Shell ovate, triangular, apex sub-
. central; posterior end truncated, or deeply, broadly emar- ginated. Type Metoptoma pileus Phil. Geol. Yorkshire, II, p. 223, 1836. Fossil in the carboniferous formation of Great Britain. Many of the species referred to this genus by Billings and other palzontologists, clearly do not belong to it. :
The above sections, with the exception of Helcion, are well defined and will probably include the greater portion of the known species, . though some may prove distinct from any yet examined. Extensive study of the soft parts has shown, beyond dispute, that generic dis- tinctions founded on the shells alone, are wholly valueless, as the lat- ter cannot be depended upon for diagnostic characters, and many so-called genera and subgenera founded upon the shells, will fall as synonyms, or retain their places solely as the result of accident. Scutellina, as far as known, is equivalent to Acmcea. Olana, Scutel- lastra, Cellana, etc., are founded upon characters of hardly specific. value. The results of extended researches on this order are now in press, which will include a thorough revision of the synonymy in full, with a definite reference of many species to their proper position, as determined by the sum of all their characters.
Voted: To amend Article VI. of the Constitution as proposed at the meeting of May 18th.
Section of Entomology. October 26, 1870. Mr. Edward Burgess in the chair. Ten members present.
Mr. Philip 8. Sprague exhibited specimens of an Aleochara which he had discovered to be parasitic on Anthomyia cepa- rum, or an allied species, attacking the cabbage ; and of sweet corn attacked by Sitophilus oryze. He also read a letter from Mr. E. C. Rye, of London, giving the information that
1870.] ye [Minot.
*
the types of Kirby, described in the Fauna Boreali Americana, as well as in his Monographia Apum Angliz, are still in ex- istence, in the British Museum.
The following paper was read: —
Notes ON THE Fuicut or N. E. Butrerrurs. By CHARLES S. Minor,
In the course of the past summer I spent a good deal of time
investigating the flight and some of the habits of the imagines of our common New England butterflies. Though my studies on this sub- ject are far from complete, yet afew remarks may not be uninter- esting. ; My experiments and observations have not as yet extended to the mechanical principles, but merely to the character, of the flight, and the influence of certain structural differences upon it. J find that, according to their flight, the New England butterflies may be divided into three large divisions, each of which may be again divided into two or three sections, which may be further di- vided into groups, each of which will contain usually a single genus and all the species of that genus. I give an example quoting the three main divisions.
I. Flight sweeping, long, sailing.
A. Not turning often. a Strong and steady. 1. Prolonged, swift. Papilio.
II. Flight not sailing, shorter than in I, more or less undulating.
Ill. Flight jerky, generally short.
The terms which I have used above will be understood only by those who have watched the butterflies out of doors. There is another division, more artificial but equally possible, which has no immediate connection with the flight, which I give below.
Genera, the individuals of which, if disturbed, return after a short interval to the same spot.
I. Usually; as Thecla, Grapta, Hesperia, etc.
II. Seldom ; as Melitza, Pieris, ete.
I will speak only of one or two of the other facts that I have noticed. A large thorax which allows room for powerful muscles, with a stiff crust, which gives a firm point from which the muscles can act,
Minot.] 56 . : [October 26,
indicate that the flight of the insect will be powerful and zig-zag. The shape of the wing also exerts great influence; e.g., a shoul- dered costa adds strength to the wings and therefore to the flight;* or again, if the wings are very broad, the insect finds difficulty in moving them, and the flight becomes slow and unsteady. The abdo- men is used as arudder. It is by means of this that dragon-flies can turn so quickly. It may be well to mention here that all insects turn, during flight, in one of two ways: first, as in the case of the butterflies, by making a decided angle, the result being a zig-zag course ; second, as in the dragon-flies, by making a curve, the course through the air becoming a series of curves, each of which is tangent to the preceding one. Numerous examples in confirmation of my views might be adduced.
The position of butterflies when at rest, I have studied in some
detail, and have arrived at some interesting results. A great variety is found in their postures by day, but they are all different from those which are assumed by night, which are almost exactly the same for every individual of the same species. _ Having often been asked where insects spend the night, I selected two of our commonest species, Colias Philodice Godt, and Pieris rape Schrank, and watched them for a great many evenings. A little be- fore sundown they begin to alight in the grass very frequently ; as it grows later they become more and more inactive, until finally they will allow themselves to be trodden upon, pinned, and handled in any way.- Before the twilight is ended they creep down, or descend in some manner, I know not how, to the very roots of the stalk or blade of grass they have selected for their resting place. They always choose a perpendicular stalk. ‘The wings are raised over the back, with the outer edges pressed together. The antenne are kept nearly perpendicular to the axis of the body and are almost concealed be- tween the front edges of the fore-wings.
Mr. F. G. Sanborn exhibited specimens of Lepidoptera from California and Neuroptera and Geometride, presented by Dr. G. F. Waters; also insects purchased of G.,W. Belfrage, of Texas, and a collection made by Prof. A. 8. Bickmore, in Southern Asia.
1 Wallace, Contrib. Nat. Selec., p. 179, also has noticed this fact.
1870.] Si | (Shaler.
Wednesday, November 2, 1870.
The President in the chair. Thirty-nine persons present.
Prof. N. S. Shaler made a verbal communication on the changes which have taken place on the Atlantic Coast; and especially on the denuding action of ice.
Mr. E. Bicknell referred to the flexible, muscular prepara- tions exhibited by Dr. Dwight, at a previous meeting, and called the attention of the Society to some specimens of human muscle, and that of a turtle, (the glistening character of the latter still preserved) which he had prepared with equal parts of alcohol, glycerine and water. These preparations he had found useful for microscopical examination and dissec- tion.
- Second and final action was taken on the proposed amend- | ment of Article VI. of the Constitution, and it was
Voted: That Article VI. of the Constitution, be amended by in: serting the words ‘‘ after having been nominated at a preceding meet- ine” ; so that the article shall read, officers shall be chosen by ballot, after having been nominated at a preceding meeting, and a majority of votes shall be sufficient for a choice.
Section of Microscopy. November 9, 1870. Mr. E. Bicknell in the chair. Seventeen members present.
Calvin Ellis, M. D., Thomas Dwight, Jr., M. D., Alpheus Hyatt, G. F. Marden, C. 8. Minot, and J. A. Swan, were elec- ted members of the Section.
Bicknell.] 58 [November 16, |
Mr. Bicknell remarked that he had found great numbers of Tsthmia nervosa on the fronds of a species of Callitham- nion, off Portland harbor, yet the mud dredged from the | same place contained none of their frustules; he could ac_ count for their total disappearance only by supposing them to have been absorbed by the water.
Prof. A. Hyatt referred to some points in the embryology of the fossil Nautiloids, discovered by a microscopic examina- tion of the umbilici of some fossil specimens. He showed that the embryos of the same age are quite variable in their mode of development. '
Mr. A. Tuttle described a form of Paramecium, from Fresh Pond, Cambridge, differing from the common species in having a much smaller vestibule, occupying only one-fifth of the length and one-eighth of the breadth of the animal.
Mr. Bicknell described the structure of whalebone. He said the lamella were composed of a single row of: hairs set closely together and united into a plate at the base by a horny sheathing, while their ends were free. These hairs are hollow throughout their entire length, and he thought each one probably contained a nerve-fibre.
*
Wednesday, November 16, 1870.
The President in the Chair. Fifty persons present.
Count Pourtales made some remarks on the constitution of the bottom of the ocean off the east coast of the United States, south of Cape Hatteras, as developed by the sound- ings and dredgings of the U, 8. Coast Survey,
1870.] 59 [Pourtales.
The chief constituent is silicious sand from the coast line to about the one hundred fathoms line, a limit which also coincides nearly with the inner edge of the Gulf stream for a great portion of its course. Outside of this line the whitish calcareous mud, also called Globige-
rina mud, prevails and extends probably under the greater part of the
ocean. The silicious sand is replaced to the southward of the Vine- yard Islands and off the eastern end of Long Island by a greenish or bluish mud, known by the navigators as the Block Island Soundings. Similar mud is found off Sandy Hook, in a range of depressions known as the mud-holes, which form a leading mark to find the entrance of New York in thick weather. In the neighborhood of New York a few rocky patches are found, which require investigation. Near Cape Fear, also, rocky bottom is sparingly found, affording a foothold to some Corals, Gorgonians, and Sponges. Otherwise the sand is pretty uniform in constitution, varying only in the size of the grain.
A remarkable deposit of green sand is found on the inner edge of the Gulf stream off the coasts of Georgia and South Carolina. The bottom consists here chiefly of living or dead Foraminifera, the cham- bers of the latter becoming filled with a silicate which injects even the finest ramifications of the canals of the shell. At first: yellow, it gradually turns green, at the same time the shell proper decays and breaks off, leaving a cast, which by attrition or conglomeration with
others often losés the characteristic form of a cast. Sometimes black pebbles are found, of which a section shows plainly the origin, due to an agglomeration of casts of Foraminifera. The dredgings made by the Coast Survey in the Straits of Florida, have revealed the existence of a large bank of deep sea plateau off the Florida reef, consisting of _ a highly fossiliferous limestone, still in process of formation from the ‘numerous shells, Echinoderms and corals, mostly new to science, which live on it at a depth of from one hundred to three hundred fathoms. Between this plateau and the reef, the bottom consists of the detritus of the reef, more or less finely comminuted, and not rich in animal life. In depths beyond the three hundred fathoms line, but with considerable variation in its limits, we find again the Globigerina mud, which also fills the greater part of the Gulf of Mexico in deep water.
The Coast Survey intends to prosecute these researches next year
with increased means,
Packard.] 60 fat ovember 16,
Dr. A. S. Packard, Jr., gave an account of the devel- |
opment of Limulus Polyphemus, the Horse-Shoe crab.
The eggs are laid near high tide mark, loose in the sand, late in | the spring and during June and July. The larva hatches in about | six weeks. Previous to hatching it bears a striking resemblance to | the Trilobites, and may also be compared with the fossil Carbonifer- | ous King Crab, Bellinurus. It passes through a very slight metamor- |
phosis, consisting of the addition of three pairs of abdominal lamelli- form feet, and is remarkably similar to the larval trilobite. For this
and other reasons he considered the Peeciloptera, or King Crabs and — their allies, the Eurypterus, Pterygotus, etc., to be a subdivision of | the Branchiopoda, which also includes the true Phyllopads and |
Cladocera.
He considered this order as having flourished most in Paleozoic | times, the living representatives being the remnants of an extensive. |
group, the missing links of which are to be sought among the Silu-
rian, Devonian, and Carboniferous strata. He regarded the known |
forms as generalized types, which preceded in time and in process
of evolution the Decapod Crustacea. The Branchiopoda pass
jhrough, either in the egg or in the larval state, a nauplius form; and to such a form, probably living in the Laurentian seas, he would trace the ancestry of the group, the order of descent being by per- haps three or more parallel lines. Huxley has compared Pterygotus tio the zoéa of a crab. The speaker extended this apt comparison to the higher Branchiopoda, and the comparison does not apparently fail when applied to Limulus, the larva of which is nearer a zoéa than
a nauplius; there being a pair of compound eyes, and a distinct |
abdomen, bearing three pair of legs, while the cephalothoracic appendages are comparable to the feet of the zoéa of the Decapods, which become by subsequent moults, mouth-organs, the true thoracic feet being added at the first moult. He likened the Neuroptera and Orthoptera, and, among Lepidoptera, the family Bombycide to the Branchiopoda, the generic forms often widely differmg among them- selves, being in fact generalized types, the links connecting them having probably perished in past geological periods.
Dr. Packard also announced the recent discovery at Salem of a new species of Pauropus, which he named Pauropus Lubbockii, in honor of the discoverer of this most remarkable type of Myriapods, which, as Lubbock has remarked, combines the characters of the
1870.] 61 [Morse.
Myriapods with other insects, while its antenne are bifid, a crusta- cean character. 3
Speculating on the probable ancestry of insects (including the Arachnids anJ Myriapods) he would trace their descent from a form resembling in some respects the hexapodous larva of Pauropus, which seems reproduced in larval Myriapods (Julus); in larval Arachnides (mites) ; and larval and degraded forms of many insects (such as the flea, louse, bat-tick, Braula, Chionea, female Anisopteryx, Ciceti- cus, the Thysanura, etc., etc.,) all showing a strong tendency to assume a hexapodous Podura-like form, which may be compared with the Nauplius form through which Fritz Miller, Dr. Dohrn, and Haeckel consider all crustaceans to pass. For this ancestral form he
had proposed the term Leptus, from the fact that like Nauplius,
which was first supposed to’ be an adult Entomostracan, the larval form of Trombidium had been described as a genus of mites under the name of Leptus, and was supposed to be an adult. The Leptus was hexapodous, and bore a general resemblance to the Podure, and the young of Pauropus, though the body (especially the abdominal portion) was not segmented. He thought there were several parallel lines of descent, diverging from some forms such as the Tardigrades or Linguatule, or both, and probably others, which again might- have descended from some terrestrial worm like Peripatus, and other generalized types of worms.
Prof. Edward 8. Morse made a few remarks on the struc- ture of the common sipunculoid worm of the coast, Phas-
— colosoma.
It occurs in the greatest abundance at Eastport, Me., living in the shells of Dentalium principally, though found in other species. The worm takes possession of the empty shell, and partially plugging it with hardened mud, forms a constricted aperture. Owing to the translucence of the animal, the internal organization can be studied to advantage. He referred to certain features in its structure, and in the character of its earlier stages, as throwing additional light on the affinities of the Brachiopods with the Vermes.
Dr. Samuel Kneeland gave an account of a visit made by him during the past summer, to the country lying about the upper Mississippi. He described the beauty and attractive-
Perry.] 62 December 7,
ness of the scenery and healthfulness of the climate. He also exhibited and presented to the Society valuable speci- mens of minerals collected during his visit, and referred to this section of the country as one possessing peculiar attrac- tions for the students of Natural History.
Rey. R. C. Waterston, by invitation, spoke briefly of his recent visit to California, and was requested to make a more extended statement at a future meeting.
December 7, 1870. Prof. A. Hyatt in the chair. Forty-four persons present.
_ The following is a brief abstract of a paper which will appear in full in the future pages of these Proceedings: — __
ON THE GLACIAL PERIOD IN NEw ENGLAND. By Rev. J. B. Prrry:
Mr. Perry introduced his communication with the remark that it contained the main results of his studies in this direction during the past fifteen years.
Proceeding at the outset to give a brief account of the indications of ice-agency, he first enumerated those furnished by the underlying rock-masses. These are erosion, as of lake-beds, and the like ; plan- | ation, as almost every newly-bared surface indicates ; also striation, as witnessed by the countless scratches and furrows on the rocky floor of the country.
Next were brought into view the facts indicative of ice-agency from the overlying material. These are such as the composition of — typical drift, it being generally different from that of the subjacent rocks; its derivation, it having been for the most part brought a short distance from the north; as well as its condition, it invariably being a heterogeneous jumble.
Indications from incidental phenomena were likewise noticed ; such as the accumulation of travelled matter, moraines being an instance};
1870.] 63 [Perry.
the location of perched rocks, they being often found in extraordi- nary abundance on isolated summits; and the position of certain old beaches, as that of the shore-remains at Ripton, Vermont. _
These, and other kindred facts, having been advanced as decisive proof of glacial agency, Mr. Perry proceeded to enquire, under what form, according to the evidence, the ice must have acted? ' Were the phenomena in question produced by icebergs, as supposed by Sir Charles Lyell and the geologists of his school, in connection with a general depression of the country? The several cited effects of gla- cial agency having been passed in review and subjected to close scrutiny, it was found that the larger proportion of them could never have been produced by icebergs; that the remainder may be better explained in another way ; that for the most part the theory of depression is entirely unsupported by facts, and therefore to be discarded.
The iceberg hypothesis having been considered, Mr. Perry next in- quired whether the results were produced in connection with a gen- eral elevation of the country, at the close of the Tertiary Era, as held by Professor Dana. It was shown that the theory of elevation is also a mere supposition, wholly unauthorized by positive evidence ; that the facts relied on for its support, as change of climate, the existence of pot-holes, of fiords, and of aérial deposits now lying beneath the level of the sea, can all be more satisfactorily explained in the light of an- other view; and that instead of an elevation of the land there was perhaps far more probably a depression of the ocean.
Having discussed the inadequacy of the theory of elevation, Mr. Perry finally noticed the theory of glaciation substantially as proposed and defended by Professor Agassiz. He inquired whether all the main facts passed in review be not just what we must suppose they would have been in case the country had been covered by an im- mense sheet of ice moving slowly southward. In the light of this view, he indicated how’ the several classes of effects indicative of ice- agency receive a simple and easy explanation, and especially that the more difficult phenomena, as perched rocks, elevated pot-holes, the Ripton Beach, tlie Berkshire boulder trains, and other kindred points, are not anomalies, but special instances and illustrations of the work- ing of the great agency characteristic of the glacial times.
Farlow.] 64 [December 7,
Dr. W. G. Farlow exhibited a collection of Marine Alge, of the eastern coast of the United States, and remarked on their geographical distribution.
The coast may be divided into three regions in which the alge present a marked difference. In the first division, extending from Cape Cod north, the Melanosperms predominate and are the dis- tinguishing mark. Of these, although the Fuci are more numerous, the Laminariacee are the most striking. The Laminaria longicruris, not rarely eighty feet long, is very abundant. It has never been found south of Cape Cod. In Europe it is found sometimes on the north of Scotland and on the coast of Norway. The Agarum Turner, the sea-colander, another of the Laminariacez, is peculiar to the coast of America north of Cape Cod. Its only other habitat is Alaska.
Of the Rhodosperms the Euthora cristata is very abundant, much more so than in any other part of the world. The beautiful Piilota serrata may almost be said to be peculiar to our coast. Its only other habitat is Norway, where it sometimes occurs. The Halos- accion is found north of Rye Beach in abundance, but as its fruit has never been seen, its scientific position is still doubtful.
The Chlorosperms, although rich in species, are limited to few genera, the Cladophore outnumbering all the others. The beautiful Siphonacee, the highest of all the Chlorosperms, are represented only by Bryopsis plumosa.
The marine flora of New England resembles very strongly that of the north of Scotland and } Norwar
The moment we pass south of Cape Cod we have a vegetation most strikingly like that of the Adriatic in the neighborhood of Venice. Dasya elegans, Solieria chardalis, and Polysiphonia variegata are dis- tinguishing algz of both Long Island Sound and Venice. Besides these we find the extremely beautiful Grinnellia Americana, perhaps our most beautiful alga, and only found in Long Island Sound. The Chlorosperms of this region are few in number and uninteresting in character. The Melon caperme are by no means as numerous, eith- er in species or individuals, as north of Cape Cod. But in Greenport harbor we first find in a growing state a representative of the tropical genus Sargassum, Montaguci, while south of Nantucket large masses of Sargassum bacciferum, the common gulf-weed, are found floating, probably brought from the Gulf of Mexico by the GulfStream. The
%
1870.] 65 [Farlow.
Long Island alge, it will be seen, are distinguished by the predomi- nance of Rhodosperms.
The coast, from New Jersey to South Carolina, is a desert as far as alow are concerned. In Charleston harbor we find a few alga, principally Grateloupia Gibbesii and Delesseria hypoglossum, but when we reach Key West we find a subtropical flora forming the third region into which our shore is usually divided by algologists.
Here the Fuci are wanting, and the Melanosperms are represented by Sargassum and several genera of Dictyotace. The Rhodosperms are very numerous and interesting, but it is in the number and high- ly organized character of the Chlorosperms that this region surpasses the two previously mentioned. The Siphonacee are numerous and extremely beautiful, forming large green patches near the shore, and resembling Lycopods and the larger mosses. They even have a creeping subterranean stem, as the Lycopods, by which they are able to remain fixed in the sand where very few alge can grow.
Dr. Farlow closed by showing specimens and explaining the struc- ture of the calcareous Chlorosperms of this region called corallines. The genus Udotea and Penicillus seem to be badly limited by Harvey. In Udotea flabellata we have the type of that genus. The filaments here branch at their end into root-like expansions, forming the surface of the frond, and the calcareous coating is uniform. In Udotea conglutinata the filaments are undivided at the end, but in the stipe give off lateral root-like processes and their calcareous coat- ing is cribriform. In Penicillus capitatus we have a precisely similar structure, except that the calcareous coating surrounds each filament, while in Udotea we have it uniting the filaments into a flat frond. But in Penicillus Pheniz we have the connecting link where the filaments are united into plates by threes. Dr. Farlow showed a new species of Udotea from Cuba nearly related to Udotea conglutinata.
December 21, 1870. The President in the chair. Twenty-six persons present.
GLACIER THEORY OF DriFrt. By Dr. C. T. Jackson.
Dr. C. T. Jackson made a few remarks on the conditions required for the formation of glaciers, and explained why he had not been able to adopt the glacier theory of drift phenomena.
PROCEEDINGS B. 8. N. H.—VOL. XIV. 5 JULY, 1871.
Jackson.] 66 [December 21,
He would welcome any reasonable theory to account for the origin and distribution of drift, since there were serious objections to all theories that had thus far been proposed.
The conditions absolutely necessary for the formation and move- ment of glaciers had not been proved to have ever existed in this region, or anywhere, except in mountainous countries situated in a temperate climate. We require, first, that there should be a suffi- ciently elevated temperature to provide for abundant evaporation of water; secondly, that there should be high mountains reaching the regions of perpetual snow, and such variations of temperature as would secure alternate freezing and thawing, so that neve or half melted snow, from which glaciers are formed, should be produced. Warm valleys and high mountains were then absolutely necessary for the production of glaciers. A general cooling of the globe to a tem- perature below freezing could not result in the formation of any glaciers, even if such a general reduction of temperature took place.
If the earth was ever cooled to so low a temperature we must naturally inquire how it ever became again heated. Astronomy does not justify any such hypothesis, and geological facts seem also to disprove it. We can understand the theory of Fourrier, of a slowly cooling globe, and his results are that the earth is losing but a small fraction of a degree of heat per century, owing to the imperfect conduction of heat by the thick crust of rocks. It is also shown that in the epoch immediately preceding the drift (the tertiary), that a tropical temperature pervaded the now temperate regions of the earth. The fossil remains of monkeys, tigers, and other inter- tropical animals in the north prove this fact beyond question.
If the earth, in our now temperate regions, was at the tertiary period heated to a tropical temperature, as all the facts of geology prove, how could it have been suddenly cooled to so low a degree as to allow the formation of three or four thousand feet thickness of ice in New England and other temperate countries? No facts or principles in astronomy point to any cause for such a marvelous change. Physical principles give such an assumption no support, and it derives none from paleontology and fossil botany, which indi- cate a higher, but not a lower, temperature than now exists in tem- perate and even polar regions. Witness the abundant remains of elephants in the northern Siberian soil; Mylodons in the soil of Ore- gon ; monkeys, tigers and other tropical animals in the tertiary of Iingland and other northern countries. These all indicate a warmer
)
1870.] 67 ) [Jackson,
climate at the north ages ago. Now what physical, cosmical, geolog- ical or astronomical causes can be cited to explain a cooling below zero of the earth in those regions ?
Suppose it could be proved that the whole earth was reduced in temperature to that low degree, what would follow? There would be no evaporation of water adequate to the formation of snow thou- sands of feet deep, and hence no glaciers could be produced even were the other conditions also existent.
Furthermore, it has been shown by recent experiments in France, that if the rocky crust of the globe should be cooled universally below freezing, all the water now existing on the earth’s surface would be absorbed by the pores of the rocks, for the water of our globe is kept _ at the surface only by the internal heat of the globe, and cannot pen- etrate beyond a depth of two miles without being returned as steam, which condenses into water again.
Indeed, it has been proved that if the interior of the earth consists of rocks, and the temperature of the whole earth was reduced to the freezing point, that five times the quantity of water now existing, as oceans, lakes and rivers, would be absorbed by the rocks, and every trace of humidity of the earth’s surface would disappear; and fur- thermore, that the porosity of the rocky strata would be equal to the absorption, also, of the entire atmosphere, so that the earth would be in the condition of the moon, without either water or air.
This would hardly be a state of things favorable to the formation of glaciers.
We need not go so far as this to render improbable the exist- ence of ancient glaciers in New England; for the considerations be- fore advanced are suflicient to create at least serious doubts, since the requisite conditions for their formation are wanting.
Glaciers form from partially melted snow on high mountains. In Switzerland their lower limit, or line of perpetual snow, is nine thou- sand feet elevation above the sea. A continuous supply of snow, from evaporated water in warmer regions, is required to keep up the supply in the elevated portions of the mountain.
The movement of glaciers is determined by the slopes of the mountains, the ice moving, as proved by Forbes, like a soft solid in a trough.
It is evident, also, that glaciers descend from mountains qua-qua versal, that is, go in all directions as allowed by the mountain slopes and gorges, and make their grooves and scratches in the rocky
Perry.] 68 [December 21,
bed or channel and carry their debris in all the directions pursued by the moving glacier. This does not correspond with the facts observed in drift scratches and drift deposits, for they are invariably
from north to south, deviating a little from that general course, the | most common direction of dvrift-scratches being from north-west to |
south-east in Maine, New Hampshire and Massachusetts, while in Rhode Island they run due north and south. Neither the drift scratches nor the drifted materials bear any such
relations to the hills and mountains as to indicate a glacial origin or |
movement.
American geologists are more inclined to adopt the theory of ice floes, as a drift agency, and the two or more sets of drift scratches, in the ledges, seem to be accounted for by the changing course of tidal currents, moving the grounded ice and gravel on the bottom.
It should be remembered that eight-ninths of all floating ice is below —
the surface of the water, and that ice frequently grounds at the pres- ent time on the Grand Banks, the bottom there being undoubtedly grooved in the same manner as the rocks were in the drift epoch. Dr. Jackson observed that the highest geological authorities rejected
the glacial theory of drift, and he need but name De Luc, the veteran
geologist of the Alps, Leopold Von Buch of Berlin, L. Elie De Beaumont of Paris, the most eminent geologists the world has ever seen, as stern opponents of this theory.
In response to the invitation of the President, Mr. Perry discussed at some length the objections urged by Dr. Jack- son.
As to the assertion that the glacier theory is a mere hypothesis, and that the various forms of this theory have been one after another demolished, he would frankly admit that this explanation,
in a certain sense, is an hypothesis; it cannot be proved true by a |
mathematical demonstration; no more can it be sustained by one kind of evidence alone. But that it is a mere hypothesis, he was not so ready to grant. There is a great variety of considerations bearing on the subject; the argument js cumulative. So, too, if we find, upon examination, that the main effects to be explained are substan- tilaly what we must suppose they would have been in case the coun- try were once covered by an immense blanket of ice; that there are also facts indicating the prevalence of agencies capable of forming such
|
1870.] 69 [Perry,
a wintry mass ; and that the so-called counter-facts are equally sus- ceptible of explanation according to the glacier theory, we surely have the best kind of demonstration possible in the nature of the case. Should this prove to be the fact, though he could only just touch the points now, the glacier theory must be regarded as far more than an empty hypothesis, and the various forms of its so-called demo- _lition may be counted for nought.
Another objection claiming notice is the alleged weight of author- ity against the glacier explanation. Von Buch, the greatest geolo- gist of the age, it is urged, entirely discarded this hypothesis. The same is-true of other eminent and able investigators. This argument might be good, if eminent men had never done foolish things. The opinions of distinguished savants have presumptive evidence in their favor, so long as there is nothing against them, and they are to be received not as their dicta, but because they are reasonable. While we are to have due respect for their legitimate decisions, we are also to remember that in some cases their judgments are not worth a straw ; that we are to recognize only the weight of their evidence as authority. In given points and under certain circumstances the ablest investigators have made the grandest mistakes. Most people, after passing a given age, cling tenaciously to the theories they adopted when they were younger. Early manhood is the period of inspiration. It is because young men are constantly coming upon the stage that the world moves. When a little older, these same persons, with rare exceptions, stand in the way of progress, and it must be confessed that in so doing they sometimes exert a whole- some influence, and sometimes—not. Now Von Buch (for whom he had a high veneration) was already somewhat advanced in years, and had his predilections fixed, when the youthful Agassiz first advanced the glacier theory in explanation of the drift phenomena. It is not therefore surprising that he, and other eminent geologists similarly situated, rejected, and have continued to reject it, outright.
Several other objections urged have respect to the conditions sup- posed to be necessary to the existence and action of glaciers. These are evaporation, congelation, and inclination. As these favorable conditions occur in Switzerland, so do ice-streams as their result. And the implication is that these favorable conditions have not existed in New England, and consequently that the theory of an extensive ice-sheet moving over the region is a myth. Now he would not say that the same conditions existed here in the past as are now
Perry.] 70 [December 21,
found amongst the Alps; he would simply ask whether there were conditions capable of producing the effects in question.
On the one hand, then, are there any facts indicative of conditions favorable to a sufficient supply of moisture? In order to the forma- tion of extensive ice-sheets, the water must have come mainly from the ocean. Strange to say, there is the best proof that volcanic agency was very active for some time, about the close of the ter-
tiary period. The extensive masses of erupted matter on the Pacific
coast and in Central France are, at once, instances and evidence. In connection with these disturbances, submarine volcanoes were no doubt prevalent. These must have heated the waters in the great oceanic basins, and their action being for a long time continued, the evaporation would be immense and continuous, furnishing a supply ef moisture fully equal to the demand.
On the other hand, it may be asked whether there be any facts indicative of cold at the period in question. It must be admitted that there is no positive evidence of an elevation of the northern part of North America at that time, and that thus the condition of con- gelation now existing in Switzerland did not probably prevail in this region. But there are cosmical facts suggestive of a degree of cold equal to that required in the production of the effects demanding an explanation. Without dwelling on the supposition that the earth may have been passing through a colder region of space, or on the probability that the sun is a variable body, affording sometimes. more and sometimes less heat, he mentioned three points :—
1st. Variation in the obliquity of the earth’s axis to the plane of
the ecliptic.
2d. Variation caused by the absence of the perihelion in connec- tion with the precession of the equinoxes ; and
3d. Variation in the eccentricity of the earth’s orbit.
While no one of these variations alone may be sufficient to account for the cold of the ice period, we should remember that they occur in cycles, which may be represented in round numbers by 10,500, 26,000 and 234,000 years each, and that in the course of many revolutions all the tendencies suited to produce cold must have coincided, and that thus, by the combination of intensities, there would result a great winter of the ages. Now let evaporation take place at the same time, and for a long while (and I have evidence bearing on both these points), also let the vapors from the heated basins of the ocean be borne over the cooling regions lying to the ncrth, we have just the
1870.] 71 [Perry.
conditions suggested by facts, and needful to the glaciation of the country. Whatever theory, in short, we may adopt, in regard to the ice period, the facts of astronomy compel us to admit changes of temperature—great onian summers and winters—in the progress of the globe. And geology tells the same story ; for instance, the earboniferous period followed by the permian, the miocene tertiary by the period of drift.
Again, however, it is said that, even if ice were formed, its motion would be impossible; there being no great elevation of the conti- nent, an inclined surface like that of Switzerland must haye been wanting, and thus the necessary condition of motion. Let us sup- pose North America a level plane, and that, vapors condensing, a vast amount of moisture is deposited upon it. What would be the result ? This accumulation of water cannot remain heaped up, even on a dead level, to say nothing of an inclined surface ; it must flow off. The case is not different, even if it be congealed. Ice, as influenced by gravity, would have the same tendency to motion as water. If, now, the cold on the extreme north be greater than elsewhere, there would be a barrier to motion in that direction. If melting take place to some extent on the upper surface and the southern side, wf moisture from the snows melting at midday percolate the ice which beneath the surface was much below the point of freezing, if gravita- tion does its legitimate work on a mass five or six, not to say ten thousand feet in thickness, surely some elements of motion are fur- nished, in case the ice-sheet were resting on a plane, and still more, if there were, as was no doubt the case, on the whole a gentle inclina- tion toward the Gulf of Mexico. Indeed, under such conditions, motion southward would be inevitable.
But it is also objected that, such cold prevailing, the rocks would absorb all moisture, and the surface of the earth be left, like that of the moon, without air or water. It should be remembered that the cold of the glacial period was not necessarily so intense as has been sometimes asserted, very extreme cold not being the condition most favorable, all things considered, to the production of glaciers. So it should be borne in mind, that as soon as snows and ice began to man- tle large tracts of land, they would be largely proof against external cold. Meantime, the internal heat being as intense as ever, the tem- perature of the water that penetrated the rocks would be raised, and thus an extreme absorption of moisture prevented.
Again it is asked, by way of objection, how, in case intense cold
Perry.] 12 [December 21
prevailed during the glacial period, a return of warmth was secured? If the astronomie agencies already referred to be sufficient, when taken in combination at their concurring points of greatest intensity, to occasion a winter of the ages, the same agencies would be sure to bring, in the natural course of things, an alternating sonian sum- mer. This might be a long while in coming, and the glacial period was probably of considerable duration; still it must finally appear, even as summer invariably succeeds to winter.
-Once more it is objected, that an ice-sheet moving southward | could not have produced the variations observable in the direction of the striz. It seems to be forgotten by many that the glacial mass must have varied in thickness during the different portions of the ice-period. When it was at its acme, the direction, as a rule, must have been north-southward. In the closing portion of the period, as the thickness gradually diminished, the direction would be more largely influenced by the inequalities of the country. Local glaciers finally becoming predominant, their direction must be down the existing valleys; thus in a great variety of directions, as in the Green Mountains, predominantly east-west and west-east, leaving furrows and grooves to correspond. Accordingly an ice-sheet, varying in thickness at different stages, would produce just the variations referred to, while they are hardly to be explained by resort to any other known agency.
The principal objections urged by Dr. Jackson having been con- sidered, and, as it is thought, fairly met, the hypothesis proposed in place of the glacier theory may be briefly noticed.
And, first, some geologists have maintained that the effects, referred to the agency of ice, were produced by the action of flowing water. In respect to this hypothesis, it may be simply remarked that, so far as we know, flowing water never produces, and is in no wise able to produce, some of the most characteristic features of the glacial times. In many cases the effects of its action are just the opposite of those requiring an explanation. For instance, flowing water tends to efface, not to produce, the polished surfaces met with all over the country, whenever the underlying solid rock is freshly laid bare.
Again, and this is said to be the prevailing view, icebergs and ice- floes are invoked as the all-sufficient cause of the phenomena. As to the argument involved in ‘the prevailing view,” he would simply quote, ‘‘Broad is the way of’ delusion, and the many find it.” To the
1870.] 73 [Perry.
hypothesis itself he could only devote a word. That bergs from an. arctic continent did not bring the drift, is evident from the fact that it was to a large extent derived from rocks lying only a short distance to the north of the respective places in which it is now found. It is equally clear that the great mass of typical drift was not formed by local glaciers, since it spreads in one continuous sheet, having com- mon glacial characteristics, over the whole region, while it is itself in places uncomformably overlaid by the debris of local ice-streams. That it was not dropped by slowly-thawing icebergs, either as stranded or in motion, is also apparent, since matter thus disengaged would fall particle by particle and be regularly arranged or semi- stratified, and not left in a jumble. So it is manifest that icebergs did not erode, polish and striate almost the whole rocky floor of the country, since the drift markings are made obliquely across meridional ridges, ordinarily without the slightest reference to differences of level. Indeed, for icebergs to make continuous furrows over high hills and through deep intervening valleys, irrespective of the ever- varying inequalities of surface, would be a far greater marvel than the wonders to be explained.
Having thus discussed some of the objections to the glacier theory and having briefly shown why he had never been able to adopt the iceberg hypothesis, he desired to bear witness to the great number and accuracy of Dr. Jackson’s observations of drift phenomena, and to assure him of his kindest personal regard.
After Rev. Mr. Perry’s answer, Dr. Jackson said that Mr. Perry had made an excellent defence of the glacial theory, but had not removed his objections. -He did not see how volcanoes, in distant countries, could furnish the moisture required for the production of thousands of feet of ice in New England, nor could he understand how a glacier could rise from the bottom of Lake Superior, which is more than six hundred feet below,the sea level, or how glaciers could exist in Brazil.
To the additional objections suggested by Dr. Jackson, Mr. Perry briefly replied.
As to the statement that, however effective volcanic agency may have been elsewhere, at the close of the tertiary period, it could have had little influence in New England, since there were no volcanoes
Perry.] 14 [December 21,
here, he would say that there was evidence of a great disturbance, even in this neighborhood, at the time in question. The tertiary beds of Martha’s Vineyard are tilted up at a high angle, and there are facts indicating that the uplifting took place not far from the begin- ning of the ice period. The strike of the beds suggests that the agency was also submarine; that thus the waves of the Atlantic were probably greatly heated, and the conditions furnished for immense evaporation.
The question raised in regard to the evidence of glacial agency in Brazil, requires a moment’s notice. As to the statement that the extension of the glacier hypothesis to that region is one of the great- est objections to it, he would merely say, that whether the extension be justifiable or not, it in no wise militates against the existence of ice agency in New England. As he had never visited the region, he was not prepared to discuss features which can be adequately under- stood only after the closest examination. The presumption, of course, is that Professor Agassiz has only spoken after due considera- tion, and that he is abundantly able to defend his view of the matter.
The former occurrence of ice agency in the basin of the Amazons being granted, it may be asked whether it were synchronous with the existence of drift agency in North America. After all he could learn on the subject, the observations thus far made seemed to him insufhi- cient for the decision of the question whether the drift agency of the northern hemisphere was simultaneous with that of the southern, or subsequent to it. For that reason, while he might sometimes speak of one set of cosmical agencies, and sometimes of another, he was indisposed to say, because he did not know, just which prevailed ; only that, under given circumstances, they were abundantly sufficient for the production of the facts requiring an explanation.
In respect to the assertion that, tlie bottom of Lake Superior being lower than the surface of the ocean, ice could not have moved from that basin seaward, he would say that the implied objection seems to rest on a misapprehension of the condition of things during the ice period. Let us remember that the ice, for instance, on the north shore of the lake was probably from five to ten thousand feet in thickness; that it was pressed by a portion equally thick, if not thicker, adjoining it on the north, and this by another and another ; that the basin, which was probably far more shallow at the beginning of the ice period, would be filled with ice, and greatly deepened, because of the immense force pressing from
1870.) 15 [Pickering.
above and from the north ; that thus the ice at one time in the basin must slowly pass over the southern shore, as it gradually gave way to the irresistible vis a tergo incessantly at work on the northern shore of the lake. With a caution against the indiscriminate application to ice of the conditions peculiar to the motion of water, he would illustrate the matter by a familiar instance. Water passes from Lake Superior into Lake Huron, and yet the bottom of the former is far lower than either the surface or the bottom of the latter. If there be no valid objection to this statement, he failed to see any reasonable difficulty in the supposition that ice, during the glacial period, passed from the basin of the great lake southward toward the Gulf of Mex- ico; indeed, some of the very channels which it probably eroded are visible to-day.
Dr. Charles Pickering said he found it difficult to adopt the view of Dr. Jackson, as it supposed the boulders to have been brought from a great distance. In the localities most familiar to him, he had found the boulders not far removed from their original position—a few miles only.
He thought land and water might be so distributed as to make an equal temperature on the surface of the globe. New Zealand is in a somewhat high latitude, yet produces tree ferns. At Cape Horn it is difficult to determine whether the climate is perpetual summer or perpetual winter; snow falls at intervals throughout the year, but quickly disappears, leaving the country always green; vegetation con-
_tinues uninterrupted, and the natives go without clothing.
Great geographical changes have taken place since the earlier geological periods, for the crest of the Andes was once the bottom of the ocean.
Section of Entomology. December 28, 1870.
Mr. J. H. Emerton in the chair. Nine members present.
Mr. Edward Burgess exhibited a drawing of peculiar cu- taneous muscles intersecting the nerve centre of the larva of Darapsa myron, and crossing just before the third thoracic ganglion, and causing an expansion or spreading of the gan-
Dwight.] 76 [January 4,
glionic commissure at that point. He had seen a drawing of the same muscle (numbered 18) in another species of larva in a paper by Lubbock.
January 4, 1871.
The President in the chair. Thirty-six persons present.
John P. Payson of Chelsea, John D. Billings of Jamaica Plain, G. Brown Good of Cambridge, Charles M. Sumner, M. D., Samuel Henshaw, John S. White, John Prince Knight, S. Gardner Lewis, Edward Wigglesworth, Jr., M. D., and Thomas C. Chandler of Boston, were elected Resident Members.
Mr. Henry E. Dresser of London, Josiah Curtis, M. D., of Knoxville, Tenn., and Thomas F, Perley of Bridgeton, Me., were elected Corresponding Members.
The following paper was presented:—
On Two Fowts WITH SUPERNUMERARY LEGS. By Tomas Dwicut, Jr., M. D.
Two specimens of three-legged fowls were received by the Society on December 28th, 1870, and on January 2d, 1871, respectively. Each had a third misshapen leg, which did not reach the ground, suspended between the other two; but the anatomy of the malforma- tion was entirely different in the two specimens.
The one first received (Catalogue; No. 1208) was loaded with fat. The third leg was suspended by a rounded mass of fat, in the median line below the highest caudal vertebra, and contained no bone for the first inch. A rudimentary ligament (the upper end of which was perhaps slightly muscular) descended from the ischial spine of either side, each to be inserted into one of the two spines by which the limb began. Otherwise the pedicle was
1871.] Te [Dwight.
merely fat and skin. The bony structure is as follows: (Figure 1). First come two slender spicule of bone, the left (a) nearly three- quarters of an inch in length, the right (a) somewhat shorter, con- nected by a narrow trans- verse piece. These are con- tinuous with a single irreg- ularly cylindrical bone (d) an inch and a quarter long, having at either end a pro- tuberance directed forward. To this, another bone (c), seven-eighths of an inch long, is anchylosed at a right angle so as to point forward. At the proximal end this has a small process jutting out on either side, and below it shows a com- mencing bifurcation. Next come the phalanges. On the right there are two (d?). On the left the proximal phalanx (d) may be said either to bifurcate or else Fig. 1.
to have an outgrowth from
its right side; each of these subdivisions has a small terminal phalanx which is not so well developed as that of the right toe. The proximal phalanx has also a slight knob on its outer and lower side opposite to its bifurcation. This extremity was covered with fat and skin, having ’ no other tissue. There is considerable difficulty in naming the various parts. .To begin with the phalanges ; d’ from its number of segments is evidently the hallux, the sole representative of the right foot. If we hold that d bifurcates we have two left halluces, which is absurd; but if we consider the median toe to be an outgrowth from d we shall have a left Hallux and a second toe.
C evidently represents a double metatarsus and has at its lower end somewhat the appearance of being inverted. There were remains of joints between this bone and the phalanges, but above, all the segments are codssified. The segments a, a}, and 0 are the most difficult to identify. It might be argued that 6 represents the two
Dwight.] 78 [January 4,
tibize, and a and a! the two femora, which would account for all of the. various segments; but while it is not uncommon to have a single limb become double towards its extremity, it is perhaps unheard of to have the single limb with a double origin; still more so to have it single in the middle, as at 6, and double at each end. I think it more natural to consider 6 a fusion of the two tibiz while a, and a! are prolongations of the fibula upward. ,
The other specimen (No. 1209) before dissection was “not very unlike the first. ‘The supernumerary leg was longer, thinner and separated by a greater interval from the body. ‘There were but two- |
toes, which were of an equal number of segments and of nearly equal — size. ‘The pelvis, after removal of the soft parts, was found to be very peculiar. The sacrum is deflected to the right and the caudal verte- bre very markedly so. (Fig. 2). Between the renal portion of the
1871.] 79 [Dwight.
left illum and the left ischium on one side, and the extremity of the sacrum and caudal vertebre on the other, two plates of bone are inserted, uniting with one another at a right angle by a transverse line of union (1, 2, 3,4). The upper, nearly horizontal (1, 2, 3), plate and the deflected vertebra close the space between the two iliac bones almost completely, while the lower vertical plate (2, 3, 4) shuts off about two-thirds of the opening behind.
The transverse line of union of the two plates (1-3) is an inch and a half long, with a well marked process at each end. The outer sur- face of the horizontal plate presents little to be described. The ver- tical plate has a ridge (5-4) dividing it into a right and a left por- tion, each of which is roughly triangular. There is an oval foramen (6) at the outer superior angle of the left portion, and a smaller one (7) at the left upper angle of the right portion. Viewed from within we find the upper part of the interposed bone to be divided by a framework into two fosse, of which that to the right is much the larger, and into each of which one of the lately described fora- mina opens. A careful comparison with the normal pelvic bones will show very strikingly that the upper plate of the abnormal bone cor- responds to the renal portion of the ilium, and the lower to the ischium. And what is more interesting is that the ridge on the outer side of the latter and the framework on the inner side of the former, together with the general lateral symmetry of the two halves, make it probable that they represent the fused supernumerary bones of the two sides. The viscera had been removed before the impor- tance of these homologies was evident, but the well marked addi- tional renal cavities make it very probable that there was at least one additional kidney.
A muscular bundle, having a circular attachment about half an inch in diameter, arose from the outer aspect of the vertical plate, and at a distance of an inch and five-eighths from its origin, was inserted into the summit of the third leg. (Fig.3). The chief bone (a) is two and a half inches long, compressed laterally above so as to be very slender, but expanding below to a breadth of a third of an inch; its lower end is bent forward and has a groove on the anterior surface, the posterior being plane. The lower extremity is bifid. On the anterior aspect, near the lower end, there is a small elevation shaped like a compressed V inverted. The superior end of the bone is sur- mounted by a delicate process which, turning suddenly to the right, ends in a knob. The bone appears to represent the metatarsus of
Dwight.] 80 ot [January 4, |
the two legs turned on its long axis so that the posterior surface is in front. From each of its two inferior terminations arises a toe (0) consisting of four phalanges, the right one being a trifle the longer, and each with the plantar side above. These, therefore, are the fourth digits of different feet. Although the muscu- lar fibres ceased at the upper end of the bone, tendons were continued down the limb, and the flexor tendons going to the last phalanges were very dis- tinct; on the dorsal aspect the arrange- ment was not so clear. As these ten- dons were more or less united to the periosteum of the long bone (@), the muscle can have had little action ex- cept to raise the whole limb at once. There were several good-sized blood vessels, and the whole limb had the appearance of a much higher degree of organization than that of the other specimen. These are examples of what Vrolik calls inferior lateral duplicity. As anomalies of this class are by no means fully understood, and as it is
ee
=
b Vv very rare to find two cases which re- WZ semble one another, I have thought it Fig. 3. more for the good of science to describe
the appearances accurately than to in- dulge in speculations which, in the present state of knowledge, must rest on imperfect data.
SoME INTERESTING PHENOMENA OBSERVED IN QUARRYING. By W. H. Nixes.
In working a quarry at Monson, Mass., some phenomena have been observed, which I trust will prove to be of scientific interest. For a few years, Mr. W. N. Flynt, proprietor of the quarry, and his fore- men, have observed spontaneous fractures, movements and expan- sions of the rock. Mr. Flynt called the attention of some persons interested in science to these phenomena, yet no one made them a
‘
1871.] | 81 [Niles. subject of special study. In November, 1870, he first called my at- tention to them by quite a full account of what had been observed. To me the facts were both new and interesting, and I have since made visits to the locality, that I might personally observe and study them. With the consent of Mr. Flynt and his foremen, I shall, in the present paper, give some account of the facts they have nar- rated to me, as well as of my own observations, in order that the subject may be more fully elucidated.
The quarry is located in the belt of gneiss, which lies east of the red sandstone of the Connecticut Valley. From the city of Springfield, Mass., the quarry lies east about 4° north, and at a dis- tance of about twelve miles and a half in a direct line. In going towards the quarry from Springfield, at a distance of about seven miles and a quarter in a direct course and in the town of Wilbraham, we come to the eastern edge of the red sandstone, and the base of the first range of hills forming the eastern boundary of the Connecti- cut Valley. ‘These hills of metamorphic rock reach about six hun- dred feet in height. Crossing the range to the eastward, we descend into the valley in which the village of Monson is situated. The quarry is located on a low foot-hill at the eastern base of this first range. It extends from near the crest of the hill, over quite an area upon its southern end and western side, and where the surface is only gently inclined. '
The rock at the quarry is chiefly gneiss. It is of fine, even-grained texture, quite free from impurities, and valuable for architectural purposes. The strike is north 10° east,2 and the dip is west 10° north, at an angle of 80°. The rock is not divided by planes of stratification, but a set of parallel joints, cutting transversely to the stratification, divides it into regular beds, that at a distance, might be mistaken for strata. These beds incline only about 10° from a horizontal position, and are nearly parallel to the general sur- face of the hill. They vary in thickness from a*few inches to several feet.
In quarrying, the beds are first broken at the lower or western side of the quarry. ‘The stone is then obtained by first drilling small holes in rows, parallel to the strike of the stratification, and upon the upper surface, of the beds. Into these holes wedges are driven,
_1 Since this paper was read, it has been so enlarged as to include the observations made up to the time of publication.
* Magnetic. PROCEEDINGS B. 8. N. H.—VOL. XIV. 8 AuGuBT, 187].
Niles.] 82 [January 4,
thus breaking the rock into slabs of regular form. The beds are so free from seams, and the rock is so homogeneous in structure, that pieces of great length may be obtained in this manner. Jn working from the lower side of the quarry towards the upper, the edges of those portions of the beds which are still in position, rise above each other like successive steps. The edges of these steps form nearly straight lines, parallel to the strike of the strata. When these por- tions of the beds remain sometime without being worked, cracks frequently appear along these edges. If still allowed to remain undisturbed, the fractures become more extensive, and frequently break up large quantities of the excellent stock of the bed. It has been found by experience that when these cracks first appear their extension may be prevented, and the stock preserved from fur- ther injury, by making an opening in the bed, trending in easterly and westerly directions, thus cutting it across the strike, and at right angles to the ordinary working lines. It is evident that such an east and west opening could counteract only a force which is exerted in nearly north and south directions. ‘That the force works in the direction of the strike of the strata, is still further evident upon the examination of some of these fissures. A single example may be sufficient for illustration.
When at the quarry, April 29th, 1871, I observed an irregular fracture in a bed three feet and nine inches in thickness. The frac- ture was about sixty-one feet long. ‘The northern portion of thirty- eicht feet was nearly parallel to the strike, and the southern part of twenty-three feet curved to the eastward, and was accompanied by secondary fractures near it. Commencing at the northern end of the fracture and going southward, it would be noticed that at a few places it turned suddenly to the east, and immediately to the south again, thus making two right angles in its course. At these places the very short portions of the fracture trending eastward were wider than the long ones running southward, thus showing that the great- est movement had been from the north towards the south. At that time, April 29th, the southward movement had amounted to three-sixteenths of an inch; but when I visited the quarry July 7th, it had amounted to five-eighths of an inch, though at the time, the greatest width of the crack, at any place where it followed its general north and south course, was only one-fourth of an inch. ‘Therefore the force which fractured the rock, had, moved the relieved portion southward, more by three-eighths of an inch than it had been moved westward.
1871.) 83 [Niles
Spontaneous fractures, similar to the one described above, have been visible at the quarry whenever I have visited it. Sometimes they are quite large. I measured one, July 7th, which was full four inches wide.
Another series of phenomena is exhibited at the quarry, in the spontaneous elevation of the beds and the formation of miniature anticlinals. These elevations are common, and affect beds differing in thickness. In April I observed two anticlinals which had been recently formed. In one instance, a bed one foot eight inches thick had been elevated one inch and a half. The curvature of the upper surface of this bed was most distinctly visible. From the crest of this anticlinal to the base of the northern slope, the distance was twenty-three feet. The base of the southern slope could not be de- termined on account of the debris which had accumulated there. At one end of the crest there was a crack three-sixteenths of an inch wide, trending with the fold nearly east and west, but at the other end no fracture could be seen. In the other instance the bed was three inches thick, and at the centre had been elevated one inch. A fracture extended the entire length of the crest, which trended nearly east and west, as in the preceding instance.
On the afternoon of July 7th, a little anticlinal was formed while I was at the quarry. The bed was only two inches and three-fourths in thickness. The span of the arch from north to south was five feet five inches and a half. The length of the crest was five feet and a half, and a fracture extended the entire length of it. During the’ afternoon, the portion of the bed forming the crest was elevated three inches and a quarter. The situation showed that the force which caused the elevation, was not an artificial one used in working the quarry.
According to the testimony of the persons occupied at the quarry, explosions sometimes attend the fracturing and elevation of the beds. | Mr. A. T. Wing, superintendent at the yard, says that cracking ‘sounds are very frequently heard, especially after the work of the day, and the noise attending it has ceased. Though these sounds are more frequent in warm weather, yet they are heard in winter. These explosions sometimes throw dust into the air, and he has seen stones, weighing a few pounds, thrown several feet high by them. The sound of these explosions is sometimes as loud as the blasting of rock, and in a few instances it has been even louder. At one time, after the workmen. had left the quarry, so loud a report was
%
Niles.] 84 [January 4,
heard that they supposed the powder magazine had exploded. On hastening to the spot they found that it was not the powder, but the rock, which had exploded. <A portion of a bed of nearly circular outline, and more than thirty feet in diameter and one foot in thick- ness, had been thrown up and broken. When they reached it, a portion at the centre was three feet above the surface from which it was broken, and the rock was still cracking and falling.
Another very interesting phenomenon is the expansion of the rock, as it is being quarried.
The most remarkable instance of this was observed in the autumn of 1869. By the use of more than twelve hundred wedges, a bed was split three hundred and fifty-four feet in leneth, in a line along the strike of the rock. The fracture extended from the northern and upper portion of the quarry southward, for the distance men- tioned, but could be traced no further; so that this slab, which for three hundred and fifty-four feet had been fractured from the rock, was at its lower end, still attached to the bed, apparently as firmly as ever. The stone thus partly loosened, was eleven feet wide and three feet thick. At the upper portion of the fracture it was soon noticed, that the halves of the drill holes upon the freshly broken edge of the slab were not directly opposite their corresponding halves on the edge of the parent rock, but that they had been moved fur- ther up the hill, toward the north. At the extreme lower end, the wedges were still firmly held in the rock, and there was no percepti- ble evidence of any movement. But in passing from the lower end to the upper, the first evidence of expansion was shown in only a slightly oblique position of the corresponding halves of the drill holes. Passing on, the amount of unconformability of position inereased regularly, until at the upper end it amounted to an inch and a half. Thus from the lowest wedge to the upper end, the stone was an inch anda half longer than that portion of the bed from which it had been broken. ‘There is an abundance of testimony to this instance of expansion from those engaged at the quarry, and from those who came to the locality to see the curiosity. The stone was allowed to remain in the position above described for more than two months, and during that time it was exposed to warm and cold, and to wet and dry weather; but these changes of temperature and moisture produced no perceptible difference in the amount of the expansion. As the expansion was from the lower end to the upper, gravity could. not have been a cause of the phenomenon.
1871.] 85 [Niles.
In three instances, I have had the opportunity of observing the rock, when it has been split at shorter lengths in the manner de- scribed above. In each case the expansion was suflicient to admit of measurement.
Near the upper end of the quarry, four hundred holes had been drilled into a bed, making a row one hundred and twenty-eight feet long. When the wedges had been driven sufficiently to merely frac- ture the rock, and while most of them were still firmly held, the ex- pansion amounted to one-sixteenth of an inch. The stone which had so expanded, was eleven feet wide, and three feet thick at the lower end, and five feet thick at the upper. In this example the upper end was the one attached, and the extension was southward.
Near the southern end of the quarry, a split thirty-three feet and a half long had been made. Here the slab was firmly attached to the bed at the lower end. Its width was six feet and nine inches, and its thickness one foot and eight inches. Iwas permitted to take out the wedges, when I found the expansion amounted to one eighth of inch at the upper end. I could distinctly see that it increased reg- 4 ularly in amount, from the lower end to the upper.
The other instance was in the working of a bed, the western edge of which extended in a direct line along the strike, without having been anywhere cut or fractured transversely. A row of wedges fifty- eight feet long was driven into holes upon the upper surface of the bed, and seven feet from its edge, thereby splitting the bed only along the line of the wedges. It was then necessary to cut from the western edge of the bed eastward to this fracture. The workmen attempted to do this by taking out a piece in the form of a triangle, the base of which was upon the edge of the bed, and the apex reached the upper end of the fracture. They found this a somewhat difficult task. The piece appeared to be held by something more than the tenacity of the rock, and it was necessary to break it into small pieces before it could be removed. When considerable stone had been cut away, cracking sounds were heard, and the remaining portion of the triangular mass was quickly fractured and easily re- moved. Fortwo hours I had been watching the corresponding halves of the drill holes, at the upper end of the fracture first made by the wedges, to observe at what period of the work, the expansion, if any, should take place. The halves of the holes remained perfectly conformable in position, up to the time of the cracking sounds and the loosening of the stone, but immediately upon this taking place,
Niles. ] 86 [January 4,
those upon the edge of the slab were one-fourth of an inch further to the north, than those of the parent rock.
Prof. Johnston, of Middletown, Ct., has described! “some sponta- neous movements occasionally observed in the sandstone strata in oné of the quarries at Portland, Ct.” The movements there observed, he says, are the sliding of one stratum upon another. ‘These occur whenever a stratum at the bottom of the quarry is first broken by excavating a channel in it, which trends in easterly and westerly di- rections. When such a channel has been cut only partly through the thickness of the stratum, the stone remaining at the bottom is crushed with a loud report, and the edge of the northern side moves southward about three-fourths of an inch. ‘“ These facts,” he thinks, ‘plainly show that the strata of sandstone at this place are not, at the present time, perfectly at ease in their ancient bed,” but he does not attempt to determine the cause.
Jam not aware that any other scientific man has observed and recorded facts similar to those given by Prof. Johnston. Probably such phenomena are to be observed at comparatively few localities. At many quarries the rock is so divided by loose joints, that it would quietly yield to a force, which at Monson would cause the phenomena described. From some statements made to me by persons interested in. quarrying extensive and comparatively unbroken strata, I am inclined to believe that facts of a similar character might be collected. >
When I visited Portland, the condition of the quarries gave me no opportunity for observing phenomena of the kind described by Prof. Johnston. I found, however, that the facts were well known to those who had been engaged there for a long time, through whom I was able to determine that the movements were from east of north towards west of south, or very nearly parallel to the directions of the movements at Monson. The force causing the phenomena at the two localities may be identical, for the manner of working the quarries at Portland gives no opportunity for observing fractures, elevations and expansions, like those so well shown at Monson.
Certain features in the structure of rocks, as cleavage, for example, have been considered, by eminent geologists, as evidences of severe compression; also, polished and striated surfaces have been regarded
1Proc. Am. Association for the Advancement of Science. Eighth Meeting. 1854. p. 283. | National Magazine.<