Ill) 



Fig. 4. Inner side view of the sectorial and tubercular molars of fig. 3 (upper row) 

 (Felts spel(ca). 



Fig. 5. Inner side view of the sectorial and tubercular molars of fig. 2 (Hyana spelad). 

 Fig. 7. Inner side view of the left upper sectorial and tubercular molars of the Sabre- 

 toothed Lion (Machairodiw (Fcl/.s) eidlridc/is, Cuv.). 

 Fig. 8. Working surface of the same teeth. 



Fig. 9. Working surface of the left upper sectorial and tubercular molars of Thylacoleo 

 carnifex. 



Ficc 10. Inner side view of the same teeth. 



Fi^. 11. Outer side view of the left lower sectorial molar of the extinct British Lion 



(Felis spelaa). 



Fig. 12 Outer side view of the left lower sectorial and tubercular teeth of the Thyacoleo 

 carnifex. 



Description of a mutilated Skull of Thylacoleo carnifex, and Comparison of it 

 with that in Placental and Marsupial Carnivora. 



This fossil was discovered by W. Adeney, Esq., in the bed of a lake, 80 miles south- 

 west of Melbourne. The lake is shallow and becomes almost dry in autumn ; its bed 

 is then covered with a deposit of common salt of excellent quality. The whole of this 

 part of the country is volcanic : a contiguous deeper salt lake appears to have been the 

 crater of an extinct volcano. 



The fossil is the cranial part of the skull (Plates XL XIII. XIV. and XV. fig. 1), 

 similar in size and in the development of the temporal ridges and fossas to that of a Lion. 

 It included the large sectorial tooth implanted, with a small tubercular tooth, in a portion 

 of the right superior maxillary bone, including part of the orbit and lacrymal bone 

 (Plate XL fig. \,p and fig. 2). These teeth were the homologucs of the subjects of 

 Plate VI. figs. 1, 3, 9, 10 ; and the small proportion which the brain-case or cranial 

 cavity (Plate X.) bore to the rest of the skull, with the external position of the lacrymal 

 foramen (Plate XL testified to the marsupiality of the extinct animal. For, fortu- 

 nately, the nasal process of the maxillary in the detached facial portion of the skull 

 of this Thylacoleo fitted a surface at the fore part of the cranium in such a way as to 

 demonstrate that it formed part of the same skull, completing the lower half of the 

 orbit (Plate XL fig. 1, o), of which the upper half (o) remains in the cranial portion of 

 the skull. 



The value of this additional evidence of TJiylacoleo, besides the demonstration it 

 afforded of the true affinities of the genus, consisted in the confirmation it added of 

 characters previously deduced from fragmentary specimens, and of the constancy of such 

 characters. 



