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PROFESSOR OWEN ON THE FOSSIL MAMMALS OF AUSTRALIA. 
The Photograph No. 7 includes views of five examples of the large laniariform lower 
incisors, both outer and inner surfaces of the most entire specimen being given. 
No. 1 shows the outer side of a left lower incisor wanting only the tip of the crown. 
The closed contracted end of the root is truncate. The length is 3 inches 4 lines, the 
greatest breadth from before backward 9 lines. 
No. 3 in the photograph is of the inner side of a similarly entire right incisor 
(Plate XIII. fig. 4). The ridge (d) defining the inner side from the narrow pos- 
terior facet of the crown is clearly given in this photograph, which appears to be 
the incisor removed from the socket of the subject of fig. 1, Plate XIII., the same 
mutilation of the summit of the crown being shown. The implanted end of the root 
contracts in the same degree, and shows the same truncation, as in the subject of figs. 
5 & 6, Plate XIII. 
Photograph No. 43 gives, somewhat reduced, the inner side of the fore part of the 
right ramus, showing the symphysial surface, the carnassial, and the first molar. The 
extent and shape of the symphysis, as in Plate XII. fig. 2, are here repeated with the same 
vertical extent and lower contour of the fore part of the mandible. Photograph No. 37 
is of the outer side of the same specimen, on the same scale, showing the trenchant part 
of the crown of the first molar (to i) as in Plagiaulcix. A view of the carnassial in situ , 
in a small fragment of the left ramus, showing the oblique external smooth wear of the 
trenchant tooth, is also given in photograph No. 43. 
These evidences are acceptable as testifying to the constancy of the characters of the 
lower jaw and dentition in Thylacoleo carnifex. 
§ 6. Cave-specimens and Cast of Inferior Incisor. — I have been favoured by Mr. Keefft 
with a cast of the entire inferior incisor of Thylacoleo , from the breccia-cave in Wellington 
Valley; and since penning my notes on this cast and the photographs, an entire lower 
incisor and portions of others have come to hand in the series of cave-specimens worked 
out of the masses of breccia transmitted from the Wellington caves. 
The incisor (Plate XIII. figs. 5, 6, 7) is long, subcompressed, subrecurved; the crown 
is pointed, trenchant anteriorly. The entire tooth is about equally divided into crown 
(fig. 5, cf h) and fang (ib. f) ; but the enamelled part (e), when the root-cement is scraped 
away, is longer than at first appears ; for the cement encroaches upon the enamelled 
crown in angular prolongations from the root, and further on the inner (fig. 6, c) than 
on the outer (ib. fig. 5) or hinder part (fig. 7) of the tooth. The crown becomes three- 
sided a little below the apex ( e ) ; the outer side (fig. 5, a) is broadest, and is trans- 
versely convex, the posterior border forming that of the crown. The inner side (fig. 6, 
a, d), of less breadth, is flat, but is divided by a longitudinal ridge ( d ) into two facets, 
the hinder one being the narrowest and inclining transversely to the hinder border ( n ). 
Toward the base of the crown the hind surface (A) becomes feebly concave between 
these marginal posterior ridges. 
Thus the perforating part of this tooth is strengthened by four longitudinal enamel 
