VERTEBEATA 125 



Astragalus without head ; no third trochanter 



nor superior incisors ; Dinocerata. 



The Taligrada are confined to the Postcretacic epoch ; 

 the Pantodonda to the Lower, and the Dinocerata to the 

 Upper Eocene. 



The order Proboscidia is unknown prior to Middle Neo- 

 cene time in the northern part of the Eastern and Western 

 Hemispheres, and late Neocene or Plistocene time in South 

 America. In other parts of the Southern Hemisphere they 

 are unknown, although one of the two living species (Ele- 

 phas africanus) is restricted to Africa (Fig. 60). The earliest 

 forms of Proboscidia are Dinotheria and Mastodons (Fig 61), 

 which reached huge dimensions. Elephants appear in late 

 Neocene times in India, and spread in later epehs over 

 Xojth America and Europe. In America their remains are 



a 



Fig. 60 —Elephas indicus L ; superior molar tooth, reduced. From Tomes, 

 after Owen. 



not known from south of the valley of Mexico. The hairy 

 mammoth (^Elephas primigenus Blum.) was a contemporary 

 of prehistoric man in the Old World, and probably in the 

 New. 



The DiPLARTHRA iucludc the most specialized types 'of 

 Mammalia as regards the structure of the skeleton, denti- 

 tion, and digestive system, but they are inferior to the an- 

 thropomorphous suborder of the Taxeopoda in the structure 

 of the brain. 



There are two suborders, as follows : 

 Feet with the third digit of predominating 



