12 



■TERRA NoYA " EXPEDITION. 



Recently some American writers* claim to have proved the relationship of the 

 Sparassodonts of Ameghino, Borhyaena, Prothylacinus, etc., of the Miocene of 

 Patagonia to the Tasmanian Thylacimis, ami even unite them in a family Thylacinidae, 

 distinct from the Dasyuridae : for this there seems to be hut little justification. 



Fig. 7. Skulls of A, Borhyaena tuberata (after Sinclair) ; B, Phascoloijale dorsalis (after Thomas), and <'. 

 Thylacimis rynoci-phalus ; seen from above. Phascologah lias been selected for comparison as a small 

 insectivorous type, differing from tin- large carnivorous Thylacimis in the form of tin- cranium and 

 zygomatic arch, lmt resembling it in many important structural characters. 



Tunics f lias shown that in Borhyaena the enamel of the teeth resembles in 

 structure that of Creodonts and Carnivores, lacking tubules, ami with the groups of 



11 Sinclair, Rep. Princeton Exped. Patagonia, iv, 1901, p. 333 j Gregory, Bull. Amer. .Mas. xxvn, 

 910, p. 207. 



t Proc. Zed. Soc. L906, i. p. 15. 



