1941. _Ochotona princeps utahensis_ Hall and Hayward, Great Basin Nat., 2:107, July 20, type from 2 mi. W Deer Lake, Garfield County, Utah. _Marginal records._--Utah: 9000 ft., Donkey Lake, Boulder Mtn. (Durrant, MS); type locality. OCHOTONA PRINCEPS VENTORUM A. H. Howell. 1919. _Ochotona uinta ventorum_ A. H. Howell, Proc. Biol. Soc. Washington, 32:106, May 20, type from Fremont Peak, Wind River Mts., Fremont County, Wyoming. 1924. _Ochotona princeps ventorum_ A. H. Howell, N. Amer. Fauna, 47:18, September 23. _Marginal records._--Montana: Emigrant Peak (A. H. Howell, 1924:19); Beartooth Mts. (_ibid._). Wyoming: 9600 ft., 19½ mi. E and 4½ mi. S Shell (20882 KU); head of Trappers Creek (A. H. Howell, 1924:19); Medicine Wheel Ranch, 28 mi. E Lovell (32919 KU); Needle Mtn. (A. H. Howell, 1924:19); Lake Fork (_ibid._); 8450 ft., 17½ mi. S and 6½ mi. W Lander (37994 KU); Middle Piney Lake, "near" Stanley (A. H. Howell, 1924:19); Salt River, 16 mi. S Afton (Hall and Bowlus, 1938:337); Teton Pass (A. H. Howell, 1924:19). Idaho: Teton Canyon (Davis, 1939:349). Family LEPORIDAE--Rabbits and Hares Hind legs longer than forelegs; ears longer than wide; frontal bone carrying supraorbital process consisting always of posterior arm and sometimes of anterior arm; rostrum wide; nasals not wider anteriorly than posteriorly; maxillae conspicuously fenestrated; jugal projecting less than half way from zygomatic root of squamosal to external auditory meatus (except in _Romerolagus_); pubic symphysis well marked; dental formula, i. 2/1, c. 0/0, p. 3/2, m. 3/3 (but m. 2/3 in _Pentalagus_ of Liu Kiu Islands south of Japan); second upper maxillary tooth like third in form; last lower molar double; cutting edge of first upper incisor straight; mental foramen of mandible situated under first lower cheek-tooth. Females average larger than males in all members of this family. (See Orr, 1940:20.) The reverse is true in most other families of mammals.