356 BRANCH CHORDATA 



em form; the Jack-rabbit (L. campeslris) of the West and Southwest; and 

 L. americanus, a northern variable species, whose fur turns white in winter. 

 They are not gregarious, though it is said they often play together on moon- 

 light nights. They are crepuscular and somewhat nocturnal. 



Geologic Distribution. — Rodents appeared first in America in 

 the Wasatch stage of the Eocene. Ahnost all the principal 

 groups of existing forms appeared within the tertiary.^ 



Use to Man. — Great numbers of rabbits are used for food in 

 the cities during the winter season. Their fur is used for making 



Fig. 290. — Scapula and anterior limb of Jack-rabbit. (Mounted by 

 students.) 



felt hats. " Nine-tenths of the felt hats worn in the United 

 States are made from rabbit-fur." Where they are numerous 

 or food is scarce they gnaw the bark of young fruit trees. In 

 many localities the orchard is enclosed in rabbit-proof fence. 

 Beaver skins are also much used for furs. 



Order VIII. Carniv'ora (" Mammals of Prey "). — These flesh- 

 eating mammals may be small or large. They may be terres- 

 trial, arboreal, or aquatic. They feed upon the flesh and blood 



^ Parker and Haswell, p. 574. 



