145 



fossil. There can be no doubt as to the specific identity of the Wellington Valley 

 cave-fossils with those of Thylacoleo carnifex from Melbourne (Lake Colungoolac) and 

 from Queensland (Gowrie Creek). 



The second fossil of Thylacoleo from the breccia-cave, the subject of the photograph 

 No. 29 of the series, is a smaller portion of the fore part of a right ramus, with the 

 entire incisor, the carnassial, and first molar in situ. The whole length of the base of 

 the incisor is exposed, and the obtuse termination of the closed and contracted end 

 of the root (Plate IX. fig. 2). The fractured state of the bone also shows portions of 

 the fore and hind roots of the carnassial (p 4), the latter apparently the larger, contrary 

 to that in the lower carnassial of Felines, which is not the homologous tooth, although 

 with a similar adaptive modification of crown. The length of the incisor is 3 inches 

 3 lines, that of the enamelled crown appears to be about 1 inch 8 lines ; the antero- 

 posterior breadth of its base" is 9 lines. The position, direction, and curvature of the 

 incisor in this specimen accord with those in the photograph copied in fig. 1, 

 Plate IX., and with the restoration based on the direction of the empty socket in 

 the subject of Plate XVIII. fig. 6. The vertical extent of the fore part of the carnassial 

 (p 4) is 1 inch 9 lines, that of the enamelled crown being 7\ lines. 



All the evidences yielded by the specimen (figs. 1-3, Plate VIII.), by the casts 

 (Plate XI. fig. 3), and by the photographs (Plate IX. figs. 1 & 2, p *) concur in 

 showing the closer resemblance of this sectorial tooth to the carnassial of the large pla- 

 cental Carnivores (Plate VIII. figs. 9 & 12) than to the sectorial premolar in Eat-Kan- 

 garoos (ib. figs. 8 & 10). The crown of the tooth (fig. 11) is bent lengthwise, with the 

 convexity outward, the concavity inward ; and this is chiefly at the hinder half of the 

 tooth (fig. 3, p 4). The fore part of the crown is the thickest, and that by the promi- 

 nence of the inner surface at the anterior fourth, which makes a low obtuse ridge (r, fig. 11, 

 Plate VIII.) divided by a depression or channel from the anterior ridge (a) or border of 

 the crown, which represents the prebasal ridge (a) in the carnassial of the Hijana (fig. 12). 

 The broader part of the trenchant surface (b, fig. 11) is anterior, as in Hycena (b, fig. 12). 

 The trenchant margin does not extend in a straight line, but is subconcave, though less 

 so and more continuously than in Hyaena. The effect of these curves of the cutting part 

 of the blades in Thylacoleo, as in Felis and Hycena, is to make them meet at successive 

 parts in the act of cutting, not by simultaneous opposition of the entire cutting-edges of 

 the opposed blades. The vertical undulation of the enamel is finer, less marked, in the 

 lower than in the upper carnassials, and is confined to the basal part of the inner surface, 

 not to the apical half of the crown as in Hypsiprymnus (fig. 10). 



In the cast of a specimen of a right mandibular ramus with the carnassial less worn 

 than in the specimen Plate VIII. figs. 1-3, the abraded surface is interrupted midway, 

 indicating a bilobed character of the unworn margin, as in the lower carnassial of Felines ; 

 the abraded surface in the cast expands from the unworn part of the dividing notch 

 forward toward the anterior end of the tooth and backward to the posterior end (Plate 

 VIII. fig. 11). The subject of figure 6, Plate VIII., is a specimen worked out of the 



