120 COPE 



Hemisphere. Dogs are very abundant throughout the 

 Neocene, except in the southern continents, where they do 

 not appear till the Plistocene (Fig. 37). 



The Pinnipedia appear later in geologic time than the 

 Fissipedia, no forms being known of an age prior to the 

 Middle Neocene. The earliest forms are of two types re- 

 lated to the true (earless) seals and walruses respectively. 

 Of the primitive affinities of the Pinnipedia nothing is 

 known, but they are suspected to have had connection with 

 the Creodonta. 



The Chalicotheria is a group which includes but few 

 species, which have been found in India, Europe, and 

 North America. They possibly appear in Europe in the 

 Upper Eocene, and occur in the successive stages of the 

 Neocene, beyond which they did not continue. Their 

 characters are very peculiar, including long fore legs and 

 short hind ones, with claws and digits like sloths, but den- 

 tition like perissodactyle ungulates. The largest species 

 equaled a grizzly bear. 



The order Taxeopoda includes the following suborders : 



I. ? No clavicle. 



Astragalus not interlocked laterally with the 

 tibia; fibula not articulating with cal- 

 caneum ; head of astragalus rounded ; 

 canines ; no anapophyses; Condylarthra. 



Astragalus not interlocked with tibia ; fibula 

 articulating with calcaneum ; astragalus 

 head flat ; canines ; Litopterna. 



Astragalus interlocking at side with tibia ; 

 fibula not articulating with calcaneum ; 

 head of astragalus flat ; no canines ; Hyracoidea. 



II. Clavicles present. 



