254 PROCEEDINGS OF THE ACADEMY OF [1894. 



Sitoiiijis Iirrroiii iiiijilliis is an easily recognized mountain race of 

 the long-and- naked tailed species, which I described a year ago from 

 the San Bernardino Valle}'. 



<S7fo;»//>' inacrorJiuiHS and tS'tfoim/s krenii were severally taken on 

 the mainland coast and outlying islands of northern British Columbia, 

 by the Rev. Mr. Keen, a missionary stationed on Graham Island of 

 the Queen Charlotte Group. Their separation from each other, and 

 from northwestern forms previously known, is based on an examina- 

 tion of more than one hundred skins and crania of Sitomijs taken 

 by me in 1(S!)2 at numerous localities in British Columbia and 

 Washington, including a large series from Puget Sound at the type 

 locality of S. a. ansterus; also from Vancouver Island, Lulu Island, 

 and the Cascade Mountains of Washington and British Columbia. 



Sitoiinis ainerlcanns artcmisUe is founded on a series similarly taken 

 by the writer in the arid region east of the C'ascade Mountains in 

 southern British Cohnnbia, comparisons being further made with 

 series of *SVto»(//,s from Lac La Hache in the boreal realms, 100 miles 

 farther north, and with those captured in the Selkirk and Rocky 

 Mountain Ranges, eastwajd. Aiicmwn: is to the northern Great 

 Basin fauna what S. a. )H'l)nisri'iisls is to that of the northwestern 

 Great Plains. 



The color characters given for these northwestern species are of 

 greater diagnostic value, because nearly all the specimens were taken 

 in May, June, and July, a period when seasonal changes of pelage 

 are less pronounced than in a later or earlier period of the same 

 duration. 



Incidental to these studies, it is of interest to note the occur- 

 rence of a form, apparently inseparable from the Hudson Bay type 

 of Sitomi/s aiiieric(uni.-< ardlcKs, upon the higher mountain ranges 

 of southern British Columbia, thus adding a lifth mendoer of the 

 genus to the varied fauna of this great Province. 



1. Sitomys megacephalus sp. iiov. Type, ad. 9. ^"- ■^•535, Coll. Acad. Nat. Sd., 

 I'hiia. Wdudville, Alabama; Sprinj;, 1804. Col. by H. E. .Sargont. 



De-fcriptioii. — Size large; feet small; ears large; tail about length 

 of body without the head. Color above, dark blackish-cinnamon, 

 lined with gray, darkest on back, brownest on sides. Lower sur- 

 faces dirty white, the hairs plumbeous basally. The tail is sparsely 

 haired, and colored above and beneath to match the body. Inside 

 of hams phnnbeous. Hind feet white from heel; forefeet and fore- 



