246 
PKOFESSOlt OWEN ON THE FOSSIL MAMMALS OF AUSTKALIA. 
seems to be a slight interruption in the course of the enamel at the middle of the fore 
part of the tooth, which I have noticed in some of the smaller Wombats. The enamel 
was coated by cement in the fossil. 
The succeeding molars slightly decrease in breadth of grinding- surface from the third 
(to i), the decrease being most marked in the hind lobe of the last molar. This character 
is more marked in Pliascolomys latifrons than in Phase, platyrhinus. The longitudinal 
extent of the series of five teeth in Pliascolomys medius is 2 inches 6 lines, as against 
2 inches 1 line in Phase, platyrhinus , and 1 inch 8 lines in Phase, latifrons. 
The lower incisors of Pliascolomys medius resemble in relative size those in Phasco- 
lomys latifrons, in which they are smaller than in the bare-nosed Wombats ; but the 
shape of the transverse section in Phase, medius is different (Plate XXXIV. fig. 4, i) ; 
it gives a full ellipse, 4^ by 3^ lines, with the long axis almost vertical, but obliquely 
inclined from above downward and rather inward. The enamel is thin, and limited to 
the lower half of the long procumbent tooth. They are smaller, especially narrower 
transversely, than the upper pair, and in this respect resemble the lower incisors of the 
hairy-nosed, not the bare-nosed, Wombats. 
From the proportions which the extent of the molar series bears to the length of the 
entire mandible in existing Wombats, I estimate that the lower jaw in the present 
extinct species must have been between 6 and 7 inches in length. 
§ 2. Pliascolomys magnus, Ow. — This species is founded on two portions of the upper 
jaw, one containing the entire molar series of both sides (Plate XXXV. figs. 1-4), the 
other retaining the second, third, and fourth molars of the right side. Both are from the 
freshwater deposits of Queensland. The less fragmentary specimen includes rather 
more than an inch of the diastema in advance of the molars, so much of the outer 
wall of both maxillaries as includes the malar process, and a small portion of the 
premaxillaries. 
The extent of each molar series is 3 inches 6 lines ; they run almost parallel with a 
slight curve convex outward : the least interspace between the right and left series, viz. 
at the fore part of the second molar ( d d), is 1 inch ; the greatest, viz. at the hind part of 
the last molar (to s), is 1 inch 6 lines ; the interspace between the right and left ante- 
rior teeth ( d 3 ) is 1 inch 24 lines. 
Thus, as in Pliascolomys medius, the disposition of the upper molars and general form 
of the intervening palate is after the type of the existing hairy-nosed Wombat; but 
the concavity, transversely, of the palate is even greater than in Pliascolomys medius, 
and becomes still more marked at the diastemal region. 
The malar process of the maxillary (Plate XXXV. fig. 2, 21 *) rises at the same elevation 
above the socket of the third molar as in Pliascolomys medius, showing a variety amongst 
the larger extinct Wombats which has been noted in the smaller existing speciesf . 
The prezygomatic ridge (ib. to) resembles, in its curved course, length, and narrow- 
ness, that in Pliascolomys latifrons. The maxillary anterior thereto advances and bends 
t Philosophical Transactions, 1872, p. 179, figs. 5 & 6. 
