Order UNGULATA. 



The great order of hoofed quadrupeds, to which belong horses, 

 rhinoceroses and tapirs, sheep, oxen, goats and antelopes, deer, 

 pigs, hippopotami, and their allies, together with a vast number of 

 extinct animals, is by most modern naturalists extended to include 

 the elephants and hyraces, whilst by other systematists these animals 

 are distinguished as separate orders called Proboscidea and Hyra- 

 coidea. The first view is here accepted. The order Ungulata, 

 thus defined, includes the Pachydermata and Euminantia of Cuvier. 



In general organization the Ungulates are much higher than 

 Insectivores, Bats, and Eodents, and are but little inferior to Carni- 

 vores. All the living forms are terrestrial in their habits (except 

 Hippopotamus), and all feed mainly or exclusively on vegetables. 



Fig. 150. A. Brachydont lower molar of deer (Cervus elaphiis), X 1. 

 B. Hypsodont lower molar of ox (Bos iaurus), X f . 



In all, the limbs are adapted for progression and not for prehension. 

 All are heterodont and diphyodont, and their molars have broad 

 crowns with tuberculated or ridged surfaces. The toes, except in 

 Hyrax and the CameHdas, terminate in hoofs which enclose the 

 ungual phalanges more or less completely ; in a few forms the toes 

 are connected together by the integuments, but as a rule they are 

 free. The digits of each foot vary in number from five to one. 

 Clavicles are wanting. 



Ungulates are bunodont, when the crown of the unworn molars 

 is tubercular, as in pigs ; or selenodont, when it is composed of oue 



