280 
PEOFESSOK OWEN ON THE EOSSIL MAMMALS OF ATJSTEALIA. 
ness of the front tooth at that part, which would be, at least, the same as that of the 
exserted crown of the large procumbent incisor in Protemnodon Mimas. 
Of the upper jaw and teeth of this species {Protemnodon Mimas ) my present evidence 
consists of photographs of the natural size of a specimen obtained by Professor 
Thomson and Mr. Krefft in the Breccia-cave of Wellington Valley, and deposited in 
the Museum of the Natural-History Society of Sydney, New South Wales. 
The photographs, liberally transmitted to me by the Trustees of that Museum, and 
prepared under the superintendence of their able Curator, Mr. Krefft, give an outer 
side view (Plate XXVII. fig. 1), an inner side view of part of the left premaxillary and 
teeth (ib. fig. 2), an inner side view of the premolar (ib. fig. 3), and a view of the 
grinding-surface of the two best-preserved molars (d 4, m i, left side, ib. fig. 4). These 
teeth, the premolar of the left side, and perhaps the front and second incisor are 
tolerably perfect ; the remaining teeth have suffered more or less fracture ; but the 
remains of the molar series in situ on the left side enable the requisite admeasure- 
ments and comparisons as to size to be made with the mandibular teeth of Protemnodon 
previously described. From their close accordance in this character with the mandi- 
bular teeth of Protemnodon Mimas (Plate XXVI. figs. 1-3) I refer the subject of the 
photographs to that species. 
The upper incisors, as in existing Macropodidce , are three in number in each pre- 
maxillary. The foremost (Plate XXVII. fig. 1, i i) is curved lengthwise, with the con- 
vexity forward, and has a thick enamelled crown, with the fore part convex transversely ; 
its convex cutting-edge projects slightly beyond that of the second incisor. The crown 
of this tooth {i 2 ) is smaller, less convex, and less prominent than that of the foremost one. 
The indications of the socket of the third incisor support the inference that, as in the 
large existing Kangaroos {Macropus major , Macropus ( Ospliranter ) robustus , Macropus 
( Ospliranter) rufus ), the antero-posterior dimension of the crown of that tooth exceeded 
that of the second and first incisors ; but of the precise proportions of these teeth 
exemplifying specimens are still desiderata. 
The antero-posterior extent of the incisive alveoli of the left premaxillary is 1 inch 
5 lines, that of the toothless interval between the third incisor and the premolar is 
1 inch 9 lines ; the extent of the molar series is 3 inches 2 lines. The diastema is rela- 
tively shorter than in the above-cited existing Kangaroos, and indicates a corresponding 
condition of the lower jaw, whereby, as regards length, Protemnodon resembles 
Sthenurus . 
The premolar {p 3), however, retains in the upper jaw the more simple trenchant form 
which afforded the subgeneric distinction in the homotypal tooth below. There is a 
slight expansion of the fore and hind parts of the crown, the intermediate part of the 
blade having an entire and nearly straight trenchant edge, with the indication of a low 
ridge or cingulum along the base. The corresponding part on the inner side of the 
crown (ib. fig. 3), though much less developed than in the upper premolar of Sthenurus , 
adds another character differentiating Protemnodon Mimas from Protemnodon Anak. 
