FEB., 1912. Mammats oF ILLINOIS AND WIsconsIN—CoryY. 259 
Family LEPORID. 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; 
mammz 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 
373 
formula is as follows: Milk dentition, I. = Dm. eee per- 
Skull of a Rabbit. 
* 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). 
