MAMMALS OF MINNESOTA. 175 



plate of the maxillary. Coronoid, condylar, and descending 

 processes of the mandible well developed and distinct. Tibia 

 and fibula united below. Two sub-families Murinoe and Arvico- 

 lince are here recognized. 



SUBFAMILY MURING. 



This subfamily contains a large number of sprightly animals, 

 represented very familiarly by the domestic pests, and easily 

 distinguishable from the field mice, which constitute the other 

 subfamily of the Muridce, by their slender, lithe form, large 

 eyes and ears, pointed snout, and the long tail, which is cov- 

 ered with circlets of scales. 



In this subfamily the teeth are rather adapted to an omnivo- 

 rous diet than a strictly herbivorous or gramnivorous one. 

 The incisors are rather narrow, squirrel-like, and the molars 

 are rooted and with tuberculate crowns. The skull is quite 

 different from that of arvicoline rodents. The nasal bones 

 project forward. The zygomas are abruptly curved downward, 

 the palate is simple, and the angle of the mandible not strongly 

 hamular. 



Instead of going into elaborate details it is thought better to 

 reproduce the admirable tabular statement drawn up by Dr. 

 Coues and published in Monographs of North American Roden- 

 tia, p. 45. 



NORTH AMERICA. SOUTH AMERICA. 



a. With grooved upper incisors. 



Genus OCHETODON, Coues. Form i Genus KEITHRODON, Waterh. Form 

 murine. leporine. 



b. With smooth upper incisors. 



Subgenus VESPERIMUS, Coues. Subgenus CALOMYS, Waterh. Form 



Form murine. 



Subgenus ONYCHOMYS, Baird. 

 Form arvicoline. 



Submenus ORYZOMYS, Baird. Form 



rat-like. 

 Genus HOLOOHILUS. Brandt. Form 



rat-like. 



murine. 

 Subgenus HABROTHRIX, Waterh . 



Form arvicoline. 

 Subgenus OXYMICTERUS, Waterh. 



Genus SIGMODON , Say . Form arvi- 

 coline. 



Genus NEOTOMA, Say. Form rat- 

 like. 



