402 CLASSIFICATION OF VERTEBRATES. 



SUB-ORDER 6. TOXODONTIA. 



Extinct ungulates with tri- or pentadactyl semiplantigrade feet ; alternat- 

 ing carpalia ; femur without third trochanter ; fibula articulating with the 

 calcaneum ; third toe the larger. Canines reduced, sometimes to a great 

 extent. 



FIG. 371. Skull of Typotherium cristatum. 



The Toxodons and their allies occur in the tertiary of southern South 

 America, and are as yet imperfectly known. They exhibit a strange associa- 

 tion of resemblances to perissodactyls, Hyray, elephants, and rodents. Tox- 

 odon, which persisted from the older miocene to the pleistocene, was about 

 the size of a rhinoceros. Nesodon, from the eocene. Sometimes Typotherium 

 and its allies from the same beds are separated as a distinct sub-order Typo- 

 theria. 



SUB-ORDER 7. HYRACOIDEA. 



Small plantigrade ungulates with tridactyl hind feet, fore feet four-toed, 

 the carpalia in series, the digits with nails; femur with third trochanter; 

 teeth i \* c ^ p f , m f ; placenta zonary. Only a single genus Hyrax (with 

 several sub-divisions) known, and this only in the existing fauna. The few 

 species described come from Syria, Arabia, and Africa. They live in holes 

 in the rocks, or in hollow trees, and some of the African species are arboreal. 

 One species, H. syriacus, is supposed to be the ' coney ' of the Bible. 



SUB-ORDER 8. TILLODONTA (INCLUDING T/ENIODONTA). 



Extinct plantigrade animals with pentadactyl feet ; teeth i | to , c j, 

 p | to , m f , the upper molars with three cones, the lower lophodont. 



These animals of large or moderate size recall in some respects the car- 



