1. North of 58° N latitude; underparts creamy white, without buffy wash; an indistinct grayish "collar" on shoulders _collaris_, p. 126 1´. South of 58° N latitude; underparts washed with buff; no grayish "collar" on shoulders _princeps_, p. 127 =Ochotona collaris= (Nelson) Collared Pika 1893. _Lagomys collaris_ Nelson, Proc. Biol. Soc. Washington, 8:117, December 21, type from near head of Tanana River, Alaska. 1897. [_Ochotona_] _collaris_, Trouessart, Catalogus Mammalium ..., p. 648 _Marginal records._--Alaska: Mt. McKinley (A. H. Howell, 1924:36). Yukon: head of Coal Creek, Ogilvie Mountains (_ibid._). Mackenzie: mile 63E on Little Keel River, Canol Road (Anderson, 1947:94). Yukon: _Macmillan Pass, mile 282, Canol Road_ (_ibid._); Ross River, mile 96, Canol Road (_ibid._); vic. Teslin Lake (A. H. Howell, 1924:36). British Columbia: Tagish Lake (_ibid._); Stonehouse Creek, 5½ mi. W jct. Stonehouse Creek and Kelsall River (29088 KU). Alaska: Tanana River (A. H. Howell, 1924:36). Upper parts Drab to Light Drab; underparts creamy white; grayish patch on nape and shoulders; skull broad; tympanic bullae large; total length 189; hind foot, 30. =Ochotona princeps= Pika Total length, 162-216; hind foot, 25-35; weight of _O. p. tulelata_, 6 ♂ 121 (108-128), 2 ♀ 121 and 129 grams. Upper parts varying from grayish to Cinnamon-Buff depending on the subspecies; underparts with wash of buff. Eight Nevadan females had an average of 3.1 (2-4) embryos. The mode was 3. OCHOTONA PRINCEPS ALBATA Grinnell. 1912. _Ochotona albatus_ Grinnell, Univ. California Publ. Zool., 10:125, January 31, type from 11,000 ft., near Cottonwood Lakes, Sierra Nevada, Inyo County, California. _Marginal records_ (A. H. Howell, 1924:45).--California: Bullfrog Lake; 10,000 ft., Independence Creek; type locality; Mineral King, E. Fork Kaweah River. OCHOTONA PRINCEPS BROOKSI A. H. Howell. 1924. _Ochotona princeps brooksi_ A. H. Howell, N. Amer. Fauna, 47:30, August 21, type from Sicamous, British Columbia. _Marginal records_.--British Columbia: Mountains E Shuswap Lake (Anderson, 1947:95); type locality; McGillivary Creek, Lillooet Dist. (A. H. Howell, 1924:31). OCHOTONA PRINCEPS BRUNNESCENS A. H. Howell. 1919. _Ochotona fenisex brunnescens_ A. H. Howell, Proc. Biol. Soc. Washington, 32:108, May 20, type from Keechelus, Kittitas County, Washington. 1924. _Ochotona princeps brunnescens_ A. H. Howell, N. Amer. Fauna, 47:31, September 23.