\' 



V 



/), Equiis scotti. Pleistocene, an extinct species of the genus to which modern horses belong. 

 The probable interrelationships of these and other genera are shown in the table, Figure 20.6. 

 (Courtesy American Museum of Natural History.) 



Kp^ 



m^^.c 



^ J**' 



^'-1 







J ^ 



Y! 





-^' 



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to modern horses was marked by a few general trends. These are correlated 

 with adaptations for greater speed in running and with the change in environ- 

 ment from forest to grassy plains. The trends may be summarized as follows: 

 (1) loss of side toes until only one functional digit remains in each foot, 



627 



