98 
ORIGINAL ARTICLES. 
mammalia of the Australian continent. The identification upon 
which it rests has not yet been withdrawn, so far as I am aware, by 
the author; and in his inaugural address to the British Association 
at Leeds, he re-affirms it twice, in the remarks upon the geographical 
distribution of animals.* As Professor Owen has not published 
others, it is presumed that the evidences there referred to are derived 
either from the remains received from Sir T. L. Mitchell, or from 
the molar tooth brought by Count Strzlecki. The former being of 
Diprotodon, the onus probandi now rests with the latter, which, 
also, is preserved in the Museum of the College of Surgeons. 
The specimen consists of a very perfect and intact germ of a 
back molar. The enamel shell is completely formed, but the 
pulp-nucleus had only been partially calcified, so that the ivory is 
limited to a thin layer below the enamel, and upon which the re¬ 
entering angles of the transverse ridges are distinctly visible under¬ 
neath. No part of the ivory base, or fangs, had been formed, nor is 
any trace of cement visible upon the crown-surface. The specimen 
is entire, with the exception of a slight fracture at the top of the 
inner tubercle of the front ridge, which is decurrent to the base in a 
vertical fissure of old date, being filled up with matrix. The tooth is the 
penultimate true molar (m. 2.) of the lower jaw, left side ; the crown 
is composed of three very distinct transverse ridges, divided in the 
longitudinal direction by a distinct bipartient fissure into an outer 
and inner division, each composed of a pair of high and obtusely 
conical thick points. The outer division of each ridge throws out, 
both in front and behind, a solitary outlying tubercle, attaining a 
lower elevation than the principal points. These tubercles, of the 
contiguous ridges, are connate, so as to form a bridge connecting each 
outer pair of mammillae and blocking up that part of the valley which 
lies between them, while the inner pair of points, belonging to each 
ridge, is free from accessory tubercles, thus leaving the portion of the 
dividing valleys, between the inner points, open. A small anterior 
talon, running outwards, descends around the base of the outer 
tubercle of the front ridge, and a larger posterior talon, composed of 
two or three tubercles, is appended to the posterior end of the outer 
division of the last ridge, but free from any connexion with the inner 
division of the same ridge. The tooth, therefore, belongs to the sub¬ 
genus Trilophodon , and to that section of it which may be cha¬ 
racterised by ‘ Colliculi obtusi , vallicu ] ce interrupted.'’ The necessary 
consequence of the form of the crown, as above described, is that in 
the progress of wear, when the ridges are ground down, the outer 
'* “ I have received evidences of Elephantine species from China and Australia, 
“ proving- the Proboscidian Pachyderms to have been the most cosmopolitan of 
“ hoofed quadrupeds.” (Brit. Assoc. Report, 1858, Address, p. lxxxvi.) 
“ In the formation of these recent tertiary periods, and in the limestone caverns 
“ of Australia, abundance of mammalian fossils have been found, and, with the ex- 
“ ception of the single tooth of a Mastodon, every one of them has proved to be a 
“ marsupial species.” {Idem, p. lxxxviii.) 
