999 
PROFESSOR OWEN ON THE FOSSIL MAMMALS OF AUSTRALIA. 
cement measures 1 inch 2 lines along the anterior curve. This is convex lengthwise, 
angular transversely, being traversed at the fore part by a low ridge (r, fig. 7, Plate XI.) ; 
the posterior border beyond a slight basal convexity is feebly concave lengthwise, rather 
flattened across, but chiefly bounded by a longitudinal ridge of enamel near the outer 
side : this ridge is feebly notched ; the thinner enamel is continued from it, obliquely to 
the inner side of the crown, where the thicker enamel, of less longitudinal extent than 
the outer enamel, also developes a trenchant posterior ridge. The entire length of the 
tooth following the curve is 2 inches 3 lines : the fore-and-aft breadth of the base of 
the crown is 8 lines ; the transverse breadth 5 lines : it accords, therefore, closely with 
the anterior incisor preserved in the portion of jaw above described (Plate XL figs. 1,2, 
3, i i). The photograph (No. 28 b) of the outer side of the answerable tooth shows a 
greater extent of preserved fang, though not quite entire at the end ; the serration or 
notching of the long outer hind trenchant ridge or edge of the enamel is better marked 
than in the specimen. Together they concur in demonstrating the effective laniary 
character of the foremost tooth of the upper jaw of Tliylacoleo. 
A tooth in the photograph No. 28 c of upper teeth of Tliylacoleo accords with the 
indications, as to form of fang and basal breadth of crown, afforded by the alveolus sym- 
bolized in figs. 2 & 3, Plate XI., as of the second incisor (i 2 ). I have therefore added a 
copy of it, fig. 9, in that Plate. It shows a root tapering to an obtuse point, 5 lines 
in length, and a crown 4 lines in diameter at its base, short, subconical, and obtuse, and 
may well be i 2 with a rather longer root from a less aged individual Tliylacoleo : the 
crown of this tooth must project close behind the base of the crown of the front incisor. 
The tooth (Plate XI. fig. 10) from the photograph No. 28 c', with a fang 10 lines in 
length, fitting by its fore-and-aft breadth such a socket as that marked c in figs. 1, 2, 3, 
Plate XI., answers to the indications there given. Another subject of the same photo- 
graph (fig. 11) is a more perfect canine of the opposite side, its bend of fang being con- 
trary to that indicated by the right upper socket (c) in Plate XI. 
Accordingly, I conclude the canine, c (Plate XI. figs. 9 & 10), to have a small sub- 
obtuse subcompressed crown, with a convex front outline from before backward, where 
it meets the hind shorter border of the crown at an angle which seems to form the rather 
blunt point of the tooth. The length of the enamelled crown is 4 lines, taken in the 
tooth’s axis along the middle of the crown ; the fore-and-aft breadth of the crown is 
6 lines ; the fang is an inch in length and rather curved, contracting to an obtuse point. 
Amongst the duplicate cave-teeth are the crowns with portions of the fang of two such 
canines; the best-preserved fang is similarly curved (Plate XI. fig. 12), with a subtrihedral 
transverse section ; but this form is more strongly marked in the short enamelled crown, 
the outer and inner sides meeting, anteriorly, at a trenchant border, strongly curved to 
the apex, which bends beyond the hind side (ib. fig. 12, b ) ; this is flattened transversely, 
and is feebly concave lengthwise. The enamel has much less vertical extent here than 
along the anterior trenchant convex side of the crown. The outer side is slightly 
convex, and marked in one specimen by a longitudinal linear groove (ib. fig. 10); in the 
