14G 



breccia transmitted by the Trustees of the Australian Museum, and shows the propor- 

 tions of the two roots of p 4, lower jaw. 



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. 8 in the photograph is of the inner side of a similarly entire right incisor 

 (Plato IX. 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 IX., 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 IX. 



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 VIII. 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 (m i) as in Platjiaulax. 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. 



Cave-specimens and Cast of Inferior Incisor. — I have been favoured by Mr. Krefft 

 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 IX. figs. 5, 0, 7) is long, subcompressed, subrecurved ; the crown 

 is pointed, trenchant anteriorly. The entire tooth is about equally divided into crown 

 (fig. 5, a', b) 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 (h) becomes feebly concave between 

 these marginal posterior ridges. 



