ORDER CARNIVORA. 



I449 



pm. 4 



the enormous development of the upper canines of the males, by 

 the presence of a deep descending flange in the mandibular sym- 

 physis for the protection of the latter, and the angulation of the 

 anterior extremity of this symphysis ; the structure of the carnassial 

 teeth being usually of the type of those of the existing Cats. In 

 the type genus Machcerodus (fig. 1332), which may be taken to in- 

 clude Smifodon, DreJ>a?iodo?i, and Trucifelis, there are three incisors 

 in each jaw ; the premolars in the upper jaw never exceed two, and 

 there may be either two or only one of 

 these teeth in the lower jaw ; the latter 

 variation occurring in different individuals 

 of a single species. The upper carnassial 

 (fig. 1334) is usually like that of Felis ; 

 but in the South American M. neogceus 

 (fig. 1335) it has four distinct lobes, and 

 is thus the most complex example of 

 this type of tooth that is known. This 

 genus ranges in time from the Quercy 

 Phosphorites to the Pleistocene, and is 

 found in America, Europe, Persia, and 



India. The South American M. necator «>; from the Pliocene of India. 

 stands alone among the Felidce in having 

 no foramen to the humerus. The last genus of the 

 is the curious Eusmilns, of the Quercy Phosphorites, in 

 there are only two incisors and 

 one premolar in the mandible, 

 and the descending flange of the 

 symphysis of the latter is of enor- 

 mous depth. The existence of 

 this extremely specialised form 

 at such an early epoch is note- 

 worthy ; not less so being the 

 total extinction of the Machaero- 

 donts, which, it has been suggested, 

 may be due to their excessive spe- 

 cialisation having rendered them 

 incapable of obtaining their sub- 

 sistence. 



Suborder 3. Creodonta. — 

 The members of the suborder 

 Creodonta (or Carnivora Primi- 

 genia) are all extinct, and their 

 serial position has led to much discussion. By some authorities 

 they have been classed with the Polyprotodont Marsupials ; from 

 which, however, they differ by the presence of a complete milk-den- 



Fig. I334-— Oral aspect of the 

 left upper carnassial and true 

 molar of Machcerodus sivalen- 



family 

 which 



Fig- I 335-— Right lateral view of the skulf 

 of Machcerodus neogcezis ; from the Pleisto- 

 cene of South America. Greatly reduced. 



