In most of the Ruminantia, where the molars are in a contiguous uninterrupted series, the interval from the first molar to the anterior border of the incisive bones is nearly equal to the space occupied by the molars; in some greater, in some a little less, and generally the latter. In other Ruminantia, such as the Camelida, where the anterior molars are insymmetrical with the others, and separated from them by being placed in the middle of the diasteme, this ratio does not hold; the space from the first molar to the margin of the incisives being less than the line of molars. In the Sivatherium, the molars are in a contiguous series, and if on this analogy we deduce the length of the muzzle, we get nearly 10 inches for the space from the first molar to the point of the incisives; and 28.85 inches for the whole length of the head, from the border of the occipital foramen to the margin of the incisives; these dimensions may be a little excessive, but we believe them not to be far out, as the muzzle would still be short for the width of the face, in a ruminant.

The orbits next come to be considered. The size and position of the eye form a distinguishing feature between the Ruminantia and the Pachydermata. In the former it is large and full, in the latter smaller and sunken; and the expression of the face is more heavy in consequence. In the Sivatherium the orbit is considerably smaller in proportion to the size of the head than in existing ruminants. It is also placed more forward in the face, and lower under the level of the brow. The rim is not raised and prominent, as in the Ruminantia, and the plane of it is oblique; the interval between the orbits at their upper margin being 12.2 inches, and at the lower, 16-2 inches. The longitudinal diameter exceeds the vertical in the ratio of 5 to 4 nearly, the long axis being nearly in a line from the nasomaxillary sinus across the hind limb of the zygomatic circle. From the above we infer that the eye was smaller and less prominent than in existing ruminants; and that the expression of the face was heavier and more ignoble, although less so than in the Pachydermata, excepting the horse; also that the direction of vision was considerably forwards, as well as lateral, and that it was cut off towards the rear.

This closes what we have been led to infer regarding the organs of the head. With respect to the rest of the skeleton we have nothing to offer, as we are not at present possessed of any other remains which we can with certainty refer to the Sivatherium. Among a quantity of bonest collected from the same neighbourhood with the head fossil, there are three singularly perfect specimens of the lower portions of the extremities of a large ruminant, belonging to three legs of one individual. They greatly exceed the size of any known ruminant, and excepting the Sivatherium giganteum, there is no other ascertained animal of the order, in our collection, of proportionate size to them. We forbear from further noticing them at present, as they appear small in comparison for our fossil: and besides, there are indications in our collection, in teeth and other remains, of other large ruminants, different from the one we have described.

The form of the vertebræ, and more especially of the carpi and tarsi, are points of great interest to be ascertained; as we may expect modifications of the usual type adapted to the large size of the animal. From its

See note to page 201.-SEC. ASIAT. Soc.

+ We note here a very perfect cervical vertebra of a ruminant in our possession, which must have belonged to an animal of proportions equal to that of the Sivatherium; but from certain characters, we are inclined to suspect that it is allied to some other gigantic species of ruminant, of the existence of which we have already tolerable certainty. Of the existence of the elk, and a species of Camelidæ, Lieut. Baker of the Engineers has shown us ample proof.

Third Series. Vol. 9. No. 54. Oct. 1836.

2 K

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ZOOLOGICAL SOCIETY.

(Feb. 23, continued.)—A paper by Mr. Owen was read, entitled, Descriptions of some new or rare Cephalopoda, collected by Mr. George Bennett, Corr. Memb. Z.S." The subjects referred to in it included specimens of Cranchia scabra, Leach; a small nondescript Loligo; the head and principal viscera of a Decapodous Dibranchiate Cephalopod from Port Jackson; a small nondescript species of Octopus; and a very small specimen of Argonauta hians, with its Cephalopodous inhabitant (Ocythoe Cranchii, Leach), and a large cluster of ova: all of which were exhibited, in illustration of the communication, by permission of the Curators of the Museum of the Royal College of Surgeons, of which collection they now form part.

The specimen of Cranchia scabra was taken by Mr. George Bennett in a towing net in lat. 12° 15′ S., long. 10° 15′ W.; and was at first regarded by him as a species of Medusa: and Mr. Owen observes, that from the uncommon form which this very remarkable Cephalopod presents, one cannot feel surprised that it should have been, at the first view, referred by its captor to a Radiate family, with which the Cephalopods bear, in more than one respect, an analogical relation.

As the type of its genus Mr. Owen considers the Cranch. scabra with reference to the generic characters that separate Cranchia from the neighbouring groups: from Loligo and Onychoteuthis it is distinguished by the continuity of its mantle with the dorsal parietes of the head; and from Sepioteuthis, Sepiola, and Rossia by the proportions and position of its fins. The form of the fins alone is evidently insufficient in Cephalopods for generic distinctions, as will appear from considering the variations in this respect that occur in the several species of the well-marked genus Onychoteuthis, Licht.; and also in the several species of Loligo as at present restricted, some of which, especially Lol. brevis, Blainv., make so close an approximation to Cranch. scabra in the rounded contour, as well as the terminal position, of their fins, that were it not that the exterior margin of the mantle is in all of them free on its dorsal aspect, the latter Cephalopod, notwithstanding its singular form, could not be separated generically from the Loligines on external characters alone. As in the figures published by Férussac of the Cephalopods named Cranch. cardioptera by Péron and Cranch. minima by himself, the anterior margin of the mantle appears to be free on its dorsal aspect, similarly to that of the true Loligines, it must be doubted whether these species are correctly referred to the genus Cranchia: and the same doubt may perhaps be extended to Cranch. Bonelliana, Fér., in the description of which no mention is made of the adhesion or otherwise of the mantle to the posterior part of the head. This adhesion Mr. Owen regards as an essential character of the genus.

The specimen of Cranchia scabra on which the genus was founded by Dr. Leach, having been imperfect in some of its parts, Mr. Owen carefully describes the species anew from the perfect individual ob

tained by Mr. George Bennett; which is smaller than the original specimen, measuring only 1 inch 8 lines in total length to the end of the outstretched tentacle. The body is remarkable for its great flaccidity, which is owing to the very small space occupied by the viscera: these are situated at its anterior part, and not, as in Loligopsis, at the bottom of the sac. Besides this disproportion between the bulk of the viscera and the capacity of the containing sac, Cranchia has other relations with Loligopsis in the absence of the infundibular valve, which exists in all the other Decapodous Cephalopods; and in the non-articulation of the base of the siphon by a double ball and socket joint to the internal surface of the ventro-lateral parts of the mantle. In the Decapodous Cephalopods generally the funnel is articulated to the mantle, at the anterior part of its base, by two ball and socket joints, the projection being on the mantle and the socket on the funnel; both consisting of cartilage, covered with a fine synovial membrane. The projecting cartilage is of an oval form in the Cuttle-fish: but in Loligo it forms an elongated ridge; which in Onychoteuthis commences at the anterior margin of the mantle and extends one third down the sac, forming two thin lateral cartilaginous laminæ placed rather towards the ventral aspect of the mantle: an elongated groove in the opposite sides of the funnel plays upon each of these ridges. In Loligopsis the sides of the funnel adhere to the corresponding cartilaginous lamina, which differ from the lateral cartilages of other Decapodous Cephalopods only by their greater length and tuberculated form. In Cranchia, as in the Octopoda, these cartilages are entirely wanting; but the ventral parietes of the base of the siphon become expanded, thin, and transparent; and adhere to and become continuous with the corresponding parts of the mantle.

Mr. Owen regards as new the species of Loligo referred to, and describes it under the name of Lol. laticeps: four specimens of it, the largest of which measures only 1 inch from the extremity of the mantle to the end of the outstretched tentacle, were obtained by Mr. George Bennett among the Sargasso weed, in lat. 29° N., long. 47° W. When alive they were of a fine purple colour with dark red spots. The specimens are now destitute of colour on the fins and on the under surface of the third and fourth pairs of arms, and the spots are but few on the under part of the head and mantle; on the inner surface of the first, second, and third pairs of arms the dark pigment is disposed in broad, irregularly shaped, transverse bands, passing across between each of the pairs of suckers.

The head, as is indicated by the trivial name, is comparatively broad; and the arms which it supports are relatively longer than in the Loligines generally, the second and third pairs being nearly equal in length to the trunk. The body is subcylindrical and conical, gradually diminishing in circumference till it terminates in a point at the posterior margin of the fins, which do not extend conjoined together beyond this part. The fins are terminal and dorsal, a space of about half a line intervening between their origins anteriorly, whence their bases converge and are united at the apex of

forded a free passage to the electric fluid, I concluded that my object would be fully attained by their employment in the voltaic circuit. I accordingly prepared a very thin calf's bladder, and having placed in it a coil of thin sheet copper, with a small quantity of solution of sulphate of copper, I immersed both in an earthenware pot containing a cylinder of zinc fitting close to its inner surface, and distant from the surface of the copper an inch and a quarter, and a sufficient quantity of diluted sulphuric acid, in the proportion of 5 of the acid to 100 of water; and on testing the power of this battery with the voltameter, I found that the first deflection suffered very little diminution for several hours, though I had made no alterations in the fluids used, nor in any way disturbed the arrangement (in this experiment the pot used was only two and a half inches in diameter and three deep). In a second experiment, made with the same battery and with the same solutions, having connected it with an electro-magnet of the horse-shoe form, four inches in length and five eighths in diameter, the magnet sustained 50 lbs. attached to the keeper for three hours. Having thus proved the possibility of obtaining a continuous and equally powerful current for a long period, it next became a question whether the power could not be still further increased and prolonged by the use of other conducting liquids in contact with the same quantity of metallic surface; and after a long course of experiments upon the nature of chemical action on metals in voltaic connexion, and the comparative effects of different electrolytes of different degrees of strength, the results of which I consider sufficiently important to form the subject of another paper,-I found that of the various acid, alkaline, and saline solutions tested, muriate of ammonia in the proportion of 5 parts of the saturated solution to 100 of water, gave me the best conducting fluid, combined with the least injurious action on the zinc surface; in fact, so slight that, after several days of constant action, the zinc plate, which was amalgamated, was scarcely corroded or reduced in thickness.

It next became important to examine what connexion existed between the power produced and the distance between the zinc and copper; and it appeared natural to conclude that the more remote the surface of the copper from that of the zinc, the less would be the effect produced on completing the circuit; but, as I was aware that great diversity of opinion existed upon this subject, with the view of fully satisfying myself with respect to the best mode of construction of voltaic batteries, I prepared an apparatus by means of which I was enabled most accurately to measure the increase or diminution

A single bilobed organ, of a bright orange or red colour, similarly connected with the anterior extremities of the nidamental glands, exists (as was long since pointed out by Swammerdam) in the Cuttle-fish. In Sepiola the corresponding body is single, and of a rose colour. And there exist two such bodies in a small Cephalopod taken by Capt. Ross on the shore of Boothia, which Mr. Owen has recently described under the name of Rossia palpebrosa. Considering the bright colours which these bodies commonly present, and their structure and relations to the generative apparatus, Mr. Owen feels authorized in regarding them as analogous to the suprarenal bodies, hitherto regarded as peculiar to the Vertebrate series.

The small Octopus described by Mr. Owen was obtained by Mr. George Bennett, like the Loligo laticeps, among the Sargasso weed; which forms, as it were, a bank in the midst of the ocean, affording shelter to many marine animals of littoral genera. The condition of the generative organs would appear to indicate that the specimens brought home were not adult, and the species consequently may be assumed to attain a greater size than that of the largest individual in the collection, which measures only 1 inch from the end of the sac to the extremity of the longest arm. Of the eight arms the first, or dorsal, pair is the longest, as is the case in many species of Octopus; the second pair is nearly of the same length as the first; the third pair (which in the Decapods is commonly the longest) is scarcely half the length of the first; the fourth pair is nearly two thirds of the length of the first. The musculo-membranous web, which is usually extended between the bases of all the arms in the Octopi, is in this species developed to the ordinary extent between the four dorsal arms only: the webs between the second and third arms, and the third and fourth arms, on each side, are very short; that between the fourth pair is wanting. From this peculiarity Mr. Owen proposes to name the species Octopus semipalmatus.

Its anatomy generally agrees with that of Oct. vulgaris.

The remaining specimens described by Mr. Owen are the shell and animal of Argonauta hians, Lam. They were obtained in lat. 4° S.,long. 17° W. The animal was alive at the time of its capture by Mr. George Bennett, but fell out of its shell when it was moved on the following morning. A mass of eggs was then exposed in the involuted portion of the shell, which increased so greatly in size after being put into spirit that they now occupy so much of the cavity that not more than one third of the body of the parent could be forced into it.

Referring to the fact that the Cephalopods hitherto found in the shells of each species of Argonauta have invariably presented characters as specifically distinct as those of the shells in which they were found, each species of animal having appropriated to it its own peculiar species of shell-a fact which extends not only to Arg. Argo, Arg. tuberculata, and Arg. hians, but also to an undescribed species obtained in the Indian seas by Capt. P. P. King, R.N., for which Mr. Owen proposes the name of Arg. rufa, he is disposed to believe that the shell really belongs to the animal that occurs in it.