DEC 2 6 1936 



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IV. On the Fossil Mammals of Australia. — Part II. Description of an almost entire 

 Skull of the Thylacoleo carnifex, Owm,from a freshwater deposit, Darling Downs, 

 Queensland. By Professor Owen, F.B.S., &c. 



Eeceived June 8, — Read June 15, 1865. 



I HAVE been favoured by Edwaed Hill, Esq., of Sydney, New South Wales, through 

 the kind offices of his brother-in-law Sir Daniel Cooper, Bart., with a small collection 

 of fossil remains from that part of the freshwater deposits of Darling Downs through 

 which the river Condamine has cut its bed. 



Among these fossils were parts of a broken skull, at once recognizable, by its car- 

 nassial teeth, as belonging to the same large carnivorous marsupial as afforded the subject 

 of Part I. of the present series of papers. 



On readjusting these fragments, I was gratified to find that they formed a more perfect 

 skull than the one which first indicated the genus and species, and not only confirmed 

 the marsupial character of the fossil, but supplied particulars of much value in deter- 

 mining the afiinities of Thylacoleo in the marsupial series. 



In previously reconstructing so much of the skull of the Thylacoleo as is figured in 

 Plate XI. of the 'Philosophical Transactions' for 1859, I had, for the facial portion 

 there preserved, only the guide of a small surface on the nasal process of a detached 

 maxillary bone which fitted to about half an inch of the fractured surface of the fore 

 part of the cranium. I was glad, therefore, to have the accuracy of that ' fit ' confirmed 

 by the more perfect state of the skull here described. 



In comparing the upper carnassial tooth of Thylacoleo with that of Felis in my former 

 paper, I had to regret that a fracture, with some loss of the tooth in the marsupial car- 

 nivore, prevented the precise determination of its degree of difierence from that of the 

 placental feline in regard to the " tubercular " part of the carnassial ; but a close inspec- 

 tion of the tooth in the fossil led me to infer that " little more than the enamel " had 

 been broken away (p. 311). The perfect condition of both right and left camassials at 

 the fore part of the crown in the present instance (Plate III. p *) enables me to state that, 

 in the place of the tubercle, there is only a low vertical ridge of enamel, about a line in 

 breadth, without any additional inner root at the fore part of the tooth : the large carnas- 

 sial of Thylacoleo consists exclusively of the " blade." This is more worn than in the 

 original specimen described. A smooth and polished surface is exposed by attrition, sloping 

 from within downward and outward, and meeting the inwardly bent outer enamelled 

 surface at an angle of about 50°. The worn surface is deeper at the fore and hind parts 

 of the tooth than at the middle, agreeably with the antero-posterior concavity of the 



MDCCCLXVI. M 



