BY E. UROOM. 59 



Australian Marsupial, Thylacoleo carnifex, Owen."* In this 

 paper, while agreeing with Owen's opinion that Thylacoleo is 

 more nearly allied to the Diprotodonts than to the existing 

 carnivorous forms, he altogether differs from Owen's conclusion 

 that the animal was a carnivore. While the large premolar had 

 struck Owen as being closely paralleled by the last premolar in 

 the lion. Flower is moi'e impressed by its resemblance to the 

 homologous tooth in the Rat-kangaroo. The latter author con- 

 siders that it can be " easily shown " " that the resemblance of 

 the gi'eat premolar of Thylacoleo to the ' carnassial ' of the true 

 Carnivora is merely superficial."! " Indeed," he adds, " there is 

 no tooth, either in the upper or lower jaw, of any of the Thyla- 

 cines, Dasyures, or Opossums, that can be with any reason com- 

 pared with them [the teeth of Thylacoleo^. When, however, we 

 pass to another group of the same sub-class, the Hypsiprymni or 

 Rat-kangaroos, we see at once in the great cutting premolar a 

 miniature of that of Thylacoleo." I In support of this view he 

 points out the main features of the tooth in the Rat-kangaroos 

 and the marked degree of variability. He then considers the 

 other teeth, and concludes that " in the number and arrangement 

 of these teeth . . . Thylacoleo corresponds exactly with the 

 modern families Afacrojwdidce and Phalanyistidce, and dififers 

 completely from the carnivorous marsupials. "§ The remarkable 

 reduction of the true molars, he considers, "is evidently in relation 

 with the excessive development of the great trenchant premolar,"|| 

 and he points out that there is a tendency to reduction of the 

 true molars in the Rat-kangaroos. The small size of the brain 

 cavity and the great development of the temporal ridges he 

 considers to be " probably only a difference of the kind always 



* Q.J.G.S. 186S, p. 307. 



t Loc. cit. p. 309. 



X Loc. cit. p. 310. 



§ Loc. cit. p. 311. 



Loc. cit. p. 311. 



