MAMMALS OF MINNESOTA. 231 



they, with the hares, have descended. The hares are, however, 

 among the most widely distributed of rodents, and with the 

 squirrels are found in most parts of the world, except Australia, 

 the mice being the only family superior in this respect. 



Thus far a very few species of fossil hares have been found 

 and these are united in the genus Palceolagus, Leidy, and are 

 from the Miocene formations of America. Related species re- 

 ferred at present to the same family have been found in Pliocene 

 and later deposits also in America. The pikas (Lagomys) have 

 not yet been found fossil in America, but are known to have 

 inhabited the whole of Europe and England in Pliocene times. 

 The geographical limits of the latter group has thus been 

 greatly reduced meanwhile probably by the more extensive 

 glaciatioA of Europe. 



OSTEOLOGICAL PECULIARITIES OF LEPORID^E. 



There are long hypapophyses, or ventral median processes 

 upon the anterior lumbar vertebrae. These processes are almost 

 peculiar to the hares. The anterior thoracic vertebrae have 

 very long spines. The transverse processes of the lumbar 

 vertebrae are also very long and, with the hypapophyses, serve 

 to set off the interior muscular masses which play so important 

 a part. 



The caudal vertebrae are few and those at the base have a 

 great expansion of the transverse processes. 



The manubrium of the sternum is compressed and extended 

 forward as in other rodents in which the clavicle is rudimen- 

 tary. 



The skull has its longitudinal axis more or less strongly 

 curved, the facial surface of the maxilla is perforate and cur- 

 iously reticulated. The lachrymal bone is entirely within the 

 orbit. 



The palate in rodents is usually narrow. In the hare the 

 anterior palatine foramina are longitudinal slits of great size. 

 The part of the palate between the molars is reduced to a very 

 narrow bridge. 



The tympanic is anchylosed to the periotic and develops a 

 well marked tubular auditory meatus which is directed upwards 

 and backwards. The supraorbital process forms a great shield 

 over the eye. The hyoid arch is reduced, the basihyal being 

 compressed and keeled. 



The scapula is rather slender, the acromium is long, and 

 there is a long metacromium. In the rabbit the clavicle develops 



