350 BRANCH CHORDATA 



ern form; the Jack-rabbit (L. campestris) 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. Almost all the principal 

 groups of existing forms appeared within the tertiary. 1 



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 



1 Parker and Haswell, p. 574. 



