PROFESSOE OWEN ON THE FOSSIL MAMMALS OF AUSTRALIA. 
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cates it to have come from another and larger species than Procoptodon Pusio, yet of 
inferior size to Procopt. Goliah (Plate LXXX. fig. 7, p 3) ; the shape of the incisor 
indicates likewise a difference of species. 
The size of the remains of the two anterior fully developed molars (Plate LXXVII. 
fig. 8 , d 2, d 3), in proportion to the jaw supporting them, suggested immaturity, and the 
excavation of the bone beneath them exposed the crown and beginning of the fangs of 
a large and thick premolar, of the crushing type of the present genus. 
The outer part of the crown (ib. fig. 8, p 3 ) is divided into two subequal lobes by a 
marginal notch, from the apex of which a linear groove is continued down the outer side 
of the crown. The height of this is 6 lines, the fore-and-aft extent is 7 lines ; the breadth 
behind is 5 lines. The crown bulges out above the roots, the hinder one of which 
bifurcates 6 lines below the crown. The enamel is smooth, white, and the exposed parts 
show more or less convexity. 
The base of the broken crown of the first deciduous molar (ib. fig. 11, d 2 ) is triangular, 
with the angles rounded off and the base turned backward ; the length of the triangle is 
4 lines, the basal breadth 3 lines. The base of the next bilophodont tooth ( d 3) is sub- 
quadrate, 5^r lines in length, 5 lines in breadth. 
The diastemal tract (figs. 8, 9, & 11, l, s') has a characteristic shortness; it is con- 
tinued with, at first, a feeble concavity almost straight on to the outlet of the incisive 
alveolus, to which it slightly bends down. The outlet of the dental canal (fig. 8, v ), 
about 2 lines below the diastemal border, would be about 7 lines from the alveolar 
outlet were this entire. The lower or symphysial border (figs. 8, 9, s, s") rises to the 
alveolar outlet at a less open angle with the lower border of the horizontal ramus 
than in Sthenurus *. The syndesmotic articular surface is flat, rough, and is continued, 
well defined, to the outlet ; it indicates the generic firmer union of the rami than in 
the type Kangaroos, and a greater development of the uniting or binding structure than 
in Sthenurus f. 
The thickness of the ramus at the formative cell of the premolar, in Procoptodon 
Papha , is 10^ lines (Plate LXXVII. fig. 10). The base of the incisor (ib. figs. 8 & 9, i) 
indicates a tooth of less relative thickness than in Procoptodon Goliah. The fractured 
end gives an ovoid section 5|- lines in vertical, 3 lines in transverse diameter ; the outer 
side is moderately convex, the inner side less so : both upper and lower borders are thick 
and obtuse ; a thin coat of enamel extends from the lower upon the outer sides of the 
tooth. The shape of the working crown cannot be inferred from the basal part here 
preserved ; but this shows faint longitudinal broad impressions on the outer side, and 
also that the incisor must have risen obliquely upward at a low angle (140°) with the 
horizontal line of the molar series. 
Thus the present, like the following evidence of the genus Procoptodon , indicates, 
with the shortness and depth of the symphysial part of the jaw, the thickness of the 
crown of the lower premolar especially behind, and the thickness and apparent depth 
* Philosophical Transactions, 1874, Plate xxii. fig. 6. t Ib. ib. 
