plained on this principle. Though there is no apparent opening there for admitting the mud and animal remains, yet the seams between the beds of limestone may have been in some spots so open, as to allow the waters of the Deluge, in small quantity, to penetrate through them, before the rock was covered with alluvium ; especially as the strata might then be less compact than they are now. This water being loaded with mud and sand, mixed with animal remains, flowing backward and forward through the crevices, they were at length choaked up; the mud filling up the interstices between the beds, where we now find it. The shifting of the water through these interstices, in a horizontal direction, may serve to account for the numerous, small, rounded, and apparently water-worn, cavities in the stone, occurring at the seams; most of which cavities are filled with mud. The water might enter these horizontal seams, either at vertical cracks or clefts, or at some break in the strata, perhaps at that which formed the bed of the Wear, which flows past the front of Pallion Quarry.

The rounded holes on the floor and sides of Kirkdale Cavern indicate, that water has also flowed through it for a considerable time, and with no small violence. If a flux and reflux continued here for some time after the bones were introduced, this would serve to break and wear them rapidly. The bones, or parts of bones, that are least worn, might be protected by having portions of fleshy matter adhering to them, or might be among the last that were drifted in. I have some ends of leg-bones, or shank-bones, from the extreme parts of the cave, so rounded and worn as to resemble pebbles. I have also seen a few real pebbles from this cavern; and sand is said to have been found in some of the farthest branches. In the Manor Vale Cavern, at Kirkby Moorside, Mr Bird found bath sand, gravel, and decayed vegetable matter. But even the total absence of sand and gravel from the Kirkdale Cavern, could be no valid objection to my hypothesis ; for, in the bottom of the diluvian ocean, as in that of the present ocean, there might be spots where mud alone prevailed, as well as others where sand and gravel predominated.

The subject might admit of additional illustration, but I shall only notice farther, a fact, observed by Professor Buckland, viz. that the bases of the stag's horns found in the Cave at Kirkdale, appear to indicate that they have been shed from the head, and not broken off by violence; a fact which, according to the hypothesis advanced in this paper, may be deemed curious, as serving to point out the season of the year when the Mosaic Deluge commenced.*

Since this and the former paper (published in vol. iv.) were communicated to the Society, the author has seen good reason to exclude the horse from the list of the animals whose remains have been preserved in Kirkdale Cave. All the remains of this animal, extracted from the Cave, appear to have been thrown into it by some wags, or rogues, on purpose to increase the amount of the relics. The teeth of sheep and of hogs, as well as those of horses, have thus found their way into collections of Kirkdale bones. A horse tooth, selected from such spurious relics, has the honour of being figured in one of Professor Buckland's plates.

The specimen of jaw-bone with two teeth, noticed in vol iv. p. 263, as not identified, and of which a model was presented to the Wernerian Society, appears to belong to a small hippopotamus. The grinders of that animal are usually marked with rosettes on their masticating surface, and some teeth so marked were found in the cavern; but when the surface is worn down, the grinders correspond exactly with the two teeth in that specimen.

IX.-Observations on the Anatomy of the Pera

meles nasuta, from New Holland.

By R. E. GRANT, M. D., Professor of Zoology and Comparative Anatomy in the University of

London, F.R.S. E., F.L. S., M.W.S., &c.

(Read 26th January 1828.)

SINCE that remarkable quadruped the Virginian Opossum, with an open external pouch on the fore part of its belly for the reception and maintenance of its premature young during the period of their lactation, was first observed by navigators on the coasts of the New World, naturalists have become familiar with the singular appearance and habits of many similar Marsupial animals, by their frequent occurrence in different parts of America, in the islands of the South Pacific Ocean, in New Holland, and other parts of the East; and more than fifty species of this new and remarkable order of Mammalia have now been observed and described by authors. But notwithstanding the interesting observations of Barton, Aboville, Bell, Home, Geoffroy, Blainville, and Cuvier, on the structure and economy of these animals, the distinctive characters and living habits of many of the species are still imperfectly known, the anatomy of very few has been examined with detail, and the theory of their singular mode of gene. ration is still almost entirely conjectural. It has been long known that the young of these animals are found in a very imperfectly formed state, adhering to the points of the mammæ, which are always placed in the external pouch, and that they remain fixed by their mouth to the nipples, till they have acquired a considerable size. Marcgrave, Pison, Valentyn, Beverley, and others, supposed the ex. ternal sac to be the only uterus, and that the young are generated, as well as maintained and suckled, in that cavity. Home, Barton, and Blainville, have maintained, that the fætus in utero is not connected with the parent by a placenta, or umbilical cord; but is suspended loosely in a gelatinous matter, like the young of oviparous animals; ; while Geoffroy (Ann. des Sc. Nat. tom. ii.) more recently maintains, that the umbilical cord is distinguishable in the uterus during the embryo state of the young. Some naturalists, as Blainville and Desmarest, suppose that the young pass, in their embryo state, from the uterus directly through the parietes of the abdomen into the external sac; which M. Blainville thinks is accomplished by means of the round ligaments of the uterus (Bull. des Sc. 1818, p. 28), whose functions, in other mammalia, have not been satisfactorily ascertained: while others believe, that the premature young pass from the uterus into the vagina ; which, by projecting in an inverted state, reaches the abdominal sac, and deposites them in that cavity, or probably even attaches them to the mammæ.

The mode of generation of marsupial animals is connected with many interesting physiological inquiries; but the opportunities of observation occur so seldom in Europe, that the entire and satisfactory solution of this obscure problem must be looked for from those who enjoy favourable opportunities in the remote colonies, particularly in New Holland, of watching the progress of this function in different species, and of dissecting the recent animals in every stage of gestation.

Geoffroy de St Hilaire has removed much of the confu. sion which formerly existed in the natural history of marsupial animals, by subdividing and defining the genera, and by pointing out new and interesting anatomical relations among the species; and he has thrown much light on their physiology, by his profound and ingenious observations on the distribution of the two hypogastric arteries in these animals, and on the consequences which result from that distribution. The genus Perameles was instituted by him in 1804, for the reception of two rare species; one of which has been figured and described in the “ Naturalist's Miscellany,” and in Shaw's “ General Zoology,” from a specimen in the Hunterian Museum of London, under the name of Didelphis obesula (P. obesula of Geoffroy); the other was a new species, first described by him, and which he named Perameles nasuta, from the lengthened form of the nose. These two species are both from New Holland,

. and are among the most rare and least known of marsupial animals. They are termed Perameles, from their general resemblance to the badger, and from their possessing a distinct marsupium (from Iinga, a pouch, and meles, a badger). The two species of Perameles belong to the genus Didelphis of Linnæus and Shaw, and to the Thylaces of Illiger. There is a specimen of each species preserved in the Museum of Paris; but the descriptions of their external characters are still very imperfect and contradictory, we are still entirely unacquainted with their natural habits, and the internal structure of neither species has yet been examined. In Mr Shaw's figure of the Perameles obesula, in the Naturalist's Miscellany, two toes are represented as united under the common integuments, as far as the roots