368 THE VERTEBRATE SKELETON. 



Suborder (1). CREODONTA 1 . 



This suborder contains a number of extinct Carnivora, 

 which present very generalised characters. 



The cranial cavity is very small ; and the fourth upper pre- 

 molar and first lower molar are not differentiated as carnassial 

 teeth 2 , as they are in modern Carnivora. The Creodonta also 

 differ from modern Carnivora in the fact that the scaphoid and 

 lunar are usually separate, and that the femur has a third 

 trochanter. The feet are plantigrade. 



They resemble the Condylarthra, another very generalised 

 group, in having an ent-epicondylar foramen. 



They occurred throughout the Tertiary period in both 

 Europe and North America, and have also been found in India. 

 One of the best known genera is Hyaenodon. 



Suborder (2). CARNIVORA VERA or FISSIPEDIA. 



The skeleton is mainly adapted for a terrestrial mode of 

 life, and the hind limbs have the normal mammalian position. 

 In almost every case the number of incisors is . Each jaw 

 always has one specially modified carnassial or sectorial tooth 

 which bites like a scissors blade against a corresponding tooth 

 in the other jaw. In front of it the teeth are always more 

 or less pointed, while behind it they are more or less broadened 

 and tuberculated. In the manus the first digit, and in the 

 pes the first and fifth digits are never longer than the rest, 

 and the digits of both limbs are almost invariably clawed. 

 Some forms are plantigrade, some digitigrade, some sub- 

 plantigrade. The group includes all the ordinary terrestrial 

 Carnivora, and is divided into three sections : 



1 E. D. Cope, "The Creodonta," Amer. Natural., 1884. W. B. Scott, 

 "Revision of the N. American Creodonta," P. Ac. Philad., 1892. 



2 See next paragraph. 



