xiv ANCIENT CARNIVORES CREODONTA 455 



incommoded by the direct rays of the sun, to the effects of 



which they are very susceptible. The Elephant Seal is mild 



and inoffensive, unless enraged, and, of course, during the 

 breeding season. 



Order VIII. CREODONTA. 



This entirely extinct group of Mammalia may be thus character- 

 ised : Small to large carnivorous mammals, with skull on the 

 whole like that of the Carnivora and with trenchant teeth ; digits 

 with unguiculate phalanges ; tail long ; extremities usually with 

 five, sometimes with four digits. In the carpus a centrale is 

 present, and the scaphoid and lunar are separate. Interlocking 

 of posterior dorsal and lumbar zygapophyses very perfect. Brain 

 small but convoluted. 



This group, which corresponds with the CARNIVORA PRIMI- 

 GENIA of Mr. Lydekker, is not easy to separate absolutely from the 

 existing and more especially from some of the extinct members 

 of the CARNIVORA VERA. They also come exceedingly near the 

 Condylarthra, the presumed ancestors of the Ungulata, and like 

 them begin in the earliest Tertiary deposits. Their likeness to 

 the carnivorous Marsupials has also been insisted upon ; but it 

 would seem that the succession of teeth in the Creodonta is 

 typically Eutherian. 



The characteristics of the group may be exemplified by an 

 account of the genus Hyaenodon, after which some of the more 

 important deviations in structure shown by other genera will be 

 referred to. 



Hyaenodon is both American and European, and ranges 

 through the Eocene and the Upper Miocene. It is a much- 

 specialised Creodont, and therefore exhibits well the distinctive 

 characters of the group. About a dozen species .have been 

 described. One of the best-known is the American H. cruentus, 

 and the following description refers to it. The back part 

 of the skull is low and broad, and is compared by Professor 

 Scott (who has described this and other species) as being 

 "somewhat like that of an opossum." 1 The whole skull is 



1 Journ. Ac. Sri. Philadelphia, ix. 1886, p. 175. 



