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Bulinus Gunnii. (PI. XIX. fig. 5.)
Testa oblongo-ovalis, tenuissima anfractibus quatuor ad quinque, subventricosis, Icevigatis? sutura conspicua.
A species which resembles Bulinus granulosus in form, differing from that species, however, in being exceedingly thin. As we have only the cast of the inside, we cannot further describe it.
Locality.—In yellow limestone of Hobart Town.
This species has been named after Mr. Ronald Gunn, of Launceston, a gentleman who has materially contributed to our knowledge of the botany and natural history of Van Diemen's Land.
Helix Tasmaniensis. (PI. XIX. fig. 6.)
Testa suborbicularis, subdepressa, tenuissima, anfractibus quatuor ad quinque, ventricosis, lsevibus? ultimo extus subdeclivi; apertura fere circulari, umbilico magno; labio tenui.
This species resembles several European and Australian species in its general form, though the form of its aperture and last volution come nearest to the American Helix concava.
Locality.—With the last species.
The specimens belonging to this interesting class have been examined by Professor Owen, and by him described and illustrated in many publications, but particularly in his recent valuable Descriptive and Illustrated Catalogue of the Fossil Organic Remains, <§-c, contained in the Museum of the Royal College of Surgeons of England.
In that Catalogue, the Australian fossil Mammalia have been identified with the Marsupialia, and referred to the genus of —
We shall avail ourselves of the wonted liberality of Professor Owen, and supply the reader with an extract from his Descriptive and Illustrated Catalogue, relative to four specimens of bones belonging to Diprotodon and Nototherium, — animals new to naturalists.
"The anterior extremity of the right ramus of the lower jaw of the Diprotodon australis, Owen, exhibiting the rough articular surface of the broad and deep symphysis, the base of the large incisive tusk, the second and third molars, and the socket of the first. The third molar is the most entire; its grinding surface is produced into two high subcompressed transverse ridges, placed one before the other; there is also a ridge along both the anterior and the posterior parts of the base of the crown. The exposed commencement of the fangs is invested with a thick coating of cement; a portion of this substance also remains in the interspace between the posterior eminence and its basal ridge; the enamel is thick and presents a rugose or finely reticulate and punctate exterior, the perforations being seen at the fractured margins to lead to smooth pits, extending a little way into the enamel. The anteroposterior diameter of this tooth is two inches, the transverse diameter is one inch three lines; the extent of the three sockets of the molars is four inches five lines; they progressively diminish in size from the third to the first. The second molar is much narrower than the third, but its crown seems also to have supported two principal transverse eminences, and an anterior and posterior basal ridge: its antero-posterior extent is one inch and a half; its tranverse diameter at the posterior division, where it is thickest, is nine lines: the coronal ridges are broken off. The first molar is lost; but its socket shows that it was implanted, like the other molars, by two fangs. The anterior part of the symphysis and crown of the large incisor are broken off; from the first molar to the fractured end measures six inches three lines; this part of the margin of the jaw manifests no trace of tooth or socket. The incisor tooth extends forwards and slightly upwards; it is subcompressed, measuring one inch and a half in the vertical diameter, and nearly one inch in transverse diameter; it has a partial coating of enamel, which extends over the inferior and the lower half of the exterior surface of the tusk; the enamel has the same rugose punctate outer surface as that of the molar teeth. The large size of the dental canal exposed by the posterior fracture of the ramus indicates the ample supply of vessels and nerves which minister to the growth and nutrition of the incisive tusk; the great depth of the symphysis of the jaw gives the required strength for the operations of the tusk, and space for its support, and for the lodgement of its large persistent matrix. The vertical diameter of the symphysis anterior to the molar series is four inches. The symphysial surface, contrasted with the molar teeth, seems enormous; its antero-posterior extent to the fractured end of the jaw is six inches, its vertical diameter three inches;
its direction is obliquely from below upwards and forwards, its upper or posterior margin nearly straight, its lower or anterior one convex; it stands out a very little way from the vertical plane of the inner surface of the ramus. The thickest part of the symphysis of the jaw does not exceed three inches; this is at its lower part, which is convex in every direction. The surface of the bone seems to have been naturally roughened by minute vascular grooves and ridges; it has been crushed and cracked. The ridge, which doubtless formed the anterior part of the base of the coronoid process, begins to stand out below the socket of the third grinder; the smooth abraded surface at the back of the posterior talon of that tooth indicates the pressure against a contiguous tooth in the portion of jaw which has been broken away.
"This symphysial portion of jaw differs in a striking degree from the corresponding part in the known existing or extinct Pachyderms, which have, like the Australian extinct Mammal, a single incisor tusk in each ramus of the lower jaw. In the young Mastodon the tusk is situated in a less deep, more suddenly contracted and more produced symphysis; the symphysis of the jaw in the Sumatran and incisive Rhinoceros is much less deep, and is broader in proportion; the peculiar deflection of the symphysis in the Dinotherium makes it differ still more strikingly from the Diprotodon, in which the incisive tusks of the lower jaw extended obliquely upwards. The sudden slope of the toothless margin of the jaw anterior to the molares distinguishes the existing Proboscidians, which have a smaller anchylosed symphysis and no lower tusks.
"In the proportion of the symphysial articulation to the molar teeth, I know of no quadruped that so nearly resembles the present large Australian fossil as the Wombat; but in this Marsupial that part of the ramus of the jaw is broader in proportion to its depth: in these dimensions, viz. the proportions of breadth to depth of the jaw supporting the anterior molares, the Kangaroo more resembles the Diprotodon; and the molars of the Kangaroo in their double roots and double-ridged crowns are those amongst the Marsupials which most nearly resemble the molars in the present gigantic fossil. But the still closer resemblance which the molars of the Tapir bear to those of the Diprotodon calls for further and more decisive evidence before the supposition of its marsupial nature can be entertained with probability.
"From the alluvial or newer tertiary deposits in the bed of the Condamine River, westward of Moreton Bay, Australia."
"The proximal half of the shaft of the right femur of a quadruped as large as that to which teeth of the Diprotodon australis, Nos. 1490 to 1497 inclusive, and the femur No. 1503, belonged.
"This fragment measures eleven inches in length, and three inches in breadth at the distal fractured end, where the circumference is seven inches and nine lines, the femur there not having begun to enlarge for the formation of the distal condyles. The long and narrow trochanter minor is developed from the posterior angle of the inner border of the upper expanded part of the fragment, and resembles in form that of the gigantic femur No. 1489, though it is more posterior in position: the base of the trochanter major begins to swell outwards and forwards from the anterior angle of the