I IO 



OR GAN1C E I 'OL UTJON 



having five well-developed toes on each foot, and with short 

 and but moderately corrugated teeth (Plate 46). This is one 

 of the simplest known relatives of the hoofed mammals ; and 



Fin. 27. Skeleton of a crow (Corvns americana}. Observe that there are no teeth in the 

 jaws, that the fingers are reduced in number and partially fused together, and that the skeleton 

 of the tail is short, ending in an enlarged bone (to which the chief tail feathers are attached). 



from forms something like Phenacodus must have been 



O 



developed the elephant, rhinoceros, hog, sheep, camel, and 

 all the other hoofed mammals, including the horse and its 

 long line of ancestors. Observe the steps in the transfer- 



