PECORA 307 



from various Miocene and Pliocene deposits appear to connect the 

 modern Tragulina so closely with Greloms (p. 294), and thus with 

 the ancestral Cervi<f" , that their classification is almost an impossi 

 bility. Thus Leptomeryx, from the Miocene of the United States, 

 is regarded as a Traguloid, having four premolars in each jaw 

 and with the metatarsals fused into a cannon-bone. Prodremoth Hum, 

 of the Upper Eocene Phosphorites of France, diners in that the 

 metacarpals also form a cannon-bone ; while in the American 

 Hyperiragulus, both metacarpals and metatarsals remain separate. 

 Bachitherium, of the French Phosphorites, apparently presents 

 affinity with Grdocus, Prodremotherium, and Dorcatherium. In this 

 genus the first of the four lower premolars assumes the character 

 and function of a canine, the true canine being incisor-like, and 

 there are traces of minute upper incisors. 



Pecora, or Cotylophora. 



No premaxillary teeth or caniniform premolars. Upper canines 

 generally absent, though sometimes largely developed. Inferior 

 incisors, three on each side Avith an incisiform canine in contact 

 with them. Molariform teeth consisting of p -§, m f, in con- 

 tinuous series. Auditory bullae simple and hollow within. Odon- 

 toid process in the form of a crescent, hollow above. Distal 

 extremity of the fibula represented by a distinct malleolar bone of 

 peculiar shape, articulating with the outer surface of the lower end 

 of the tibia. Third and fourth metacarpals and metatarsals con- 

 fluent. Outer or lateral toes small and rudimentary, or in some 

 cases entirely suppressed ; their metapodial bones never complete 

 in existing forms. Navicular and cuboid bones of tarsus united. 

 Horns or antlers usually present, at least in the male sex. Left 

 brachial artery arising from a common innominate trunk, instead 

 of coming off separately from the aortic arch as in the preced- 

 ing sections. Stomach with four complete cavities. Placenta 

 cotyledonous. 1 



The Pecora or true Ruminants form at the present time an 

 extremely homogeneous group, one of the best-defined and most 

 closely united of any of the Mammalia. But, though the original 

 or common type has never been departed from in essentials, varia- 

 tion has been very active among them within certain limits ; and 

 the great difficulty which all zoologists have felt in subdivid- 

 ing them into natural minor groups arises from the fact that 

 the changes in different organs (feet, skull, frontal appendages, 

 teeth, cutaneous glands, etc.) have proceeded with such apparent 

 irregularity and absence of correlation that the different modifica- 



1 For the anatomy of this group see A. H. Garrod, Proc. Zool. Soe. 1 Q 77, p. 2. 



