THE CARNIVORES 173 



3 14 3 

 l|,Cj,PpM|.total44. 



though sometimes a tooth at the premolar-molar junction was 

 lost. The Creodonta, forerunners of the modern Carnivores, 

 were themselves derived from Mesozoie ancestors the characters 

 of which are estimated by Dr. Gregory to have been, among 

 others, the following': 'Small, semi-arboreal, insectivorous and 

 partly carnivorous Plaeentals with a dental formula: 



3. 1. 4. 3 



3. 1. 4. 3, 



a well-developed milk dentition, small tritubereular upper 

 molars, simple premolars, small simple canines, incisors of op- 

 posite sides arranged in convergent rather than transverse 

 series. The muzzle was broad and heavy, the skull constricted 

 back of the orbits, the brain-case xevy small, probably sur- 

 mounted by a long low sagittal crest, the zygomata not large. 

 Thus the ancestral Carnivores would approach the ancestral 

 Insectivores with which they had common forerunners al- 

 though they early began to assume predaceous flesh-eating 

 habits, to increase in size and to become adapted for living 

 upon the ground. 



Of the Creodonta one family, the Miacidae, small animals none 

 of which attained the size of a fox, is especially significant 

 since its members possessed so many characters in common 

 with the primitive Fissipedia that some authors class them 

 within this suborder. Perhaps one of their most striking fea- 

 tures is the constant occurrence of specialization of the last 

 upper premolar and the first lower molar for the purpose- of 

 shearing flesh. To these teeth Cuvier long ago gave the name 

 camassial: they are often now called sectorial but either term 

 is equally expressive of their function. This specialization of 



P4 



^ is found in the Fissipedia though it is not equally marked 



in all families. 



Of the Fissipedia the Dogs probably represent the central 



