FEB., 1912. MAMMALS OF ILLINOIS AND WISCONSIN CORY. 259 



Family LEPORID^E. Hares and Rabbits. 



The family is nearly cosmopolitan, various species being found in 

 North and South America, Europe, Asia and Africa, and of late years 

 in Australia where it has been introduced. Representatives of the 

 family thrive equally well in the tropics and in the cold regions of the 

 North, the range of one species extending far beyond the Arctic Circle 

 where few other mammals can exist. 



In the Hares and Rabbits the skull is large and compressed behind ; 

 the supraorbital prominent, the posterior process (postorbital process) 



being often more 

 or less fused to the 

 skull; the infra- 

 orbit a foramen 

 small land con- 

 fined to lower por- 

 tion of maxilla; 

 the incisive fora- 

 mina large, and 

 the greater portion 

 of zygoma nearly 

 straight. The max- 

 illary bones curi- 

 ously pitted and 

 perforated; the 

 upper incisors sul- 

 cate; cheek teeth rootless; acromion process of scapula forked; 

 mammae numerous, usually five pairs; uterus completely double; 

 clavicles present but incomplete; and the tibia and fibula united. 

 The wrists cannot be turned as in the Squirrels to enable the animal 

 to hold food to its mouth while eating; cheek pouches absent, but 

 the inside of mouth partly furry. They have unusually long hind 

 legs and ears; the soles of the feet are covered with fur. The tail is 

 short, the eyes large, and the upper lip is deeply cleft, giving rise to 

 the expression "hare lip" to describe a human ailment.* The dental 



-1 -2 7 7 



formula is as follows: Milk dentition, I. - ** Dm. - -=18; per- 



Skull of a Rabbit. 



I-I 



2-2 



* This is of ancient origin. Topsell says, "The lippes continually move sleeping 

 and waking, and from the slit which they have in the middle of their nose, commeth 

 the term of hare-lips" (Historie of Foure Footed Beastes, Lond., 1607, p. 265). 



