Descriptions of Five New Rodents. 223 



Peromyscus sitkensis sp. nov. 



Type from Sitka, Alaska. No. 73809, ^ ad. U. S. Nat. Mus., Biolog 

 ical Survey Coll. Collected July 30, 1895, by C. P. Streator. Original 

 No. 4720. 



General characters. Size very large much the largest of the species 

 occurring north of Mexico except P. californicus, from which it differs in 

 so many characters as to require no comparison ; tail long ; ears medium 

 or rather small ; coloration dark, in summer pelage reddish brown. 



Color. Upper parts brown, becoming russet posteriorly on back, rump, 

 and sides; ring round eye (broadest in -front of eye) and posterior aspect 

 of ankles, dusky; under parts white, the plumbeous under fur showing 

 through ; fore and hind feet whitish ; tail sharply bicolor, blackish above, 

 broadly white below; ears dusky, narrowly edged with whitish. 



Cranial characters. Skull large ; braincase rather flat; rostrum greatly 

 elongated ; pterygoid fossee unusually developed. Contrasted with the 

 skull of P. caiifomicus, the only species which equals or exceeds it in size, 

 the braincase is very much smaller and lower and the rostrum very much 

 longer. The total length of the skull is greater than in californicus, al 

 though californicus is much the larger animal. 



Measurements. Type specimen: total length, 222; tail vertebrae, 112; 

 hind foot, 26. Average of 20 specimens from type locality : total length, 

 218; tail vertebrae, 111.6; hind foot, 26.2. Cranial measurements: total 

 length, 31; basilar length of Hensel, 24; zygomatic breadth, 15; incisors 

 to postpalatal notch, 13; length of nasals, 13. 



Remarks. Apparently Peromyscus sitkensis is related to P. macrorhinus 

 (Rhoads), from Skeena River, which latter animal I have not seen. It 

 differs from P. macrorhinus in uniformly larger size, ' redder ' color, and 

 much longer nasal bones. 



Zaptis hudsonius alascensis subsp. nov. 



Type from Yakutat Bay, Alaska. No. 73584, tf ad. U. S. Nat. Mus., 

 Biological Survey Coll. Collected July 5, 1895, by C. P. Streator. Orig 

 inal No. 4660. 



General characters. Similar externally to Zapus hudsonius from northern 

 Minnesota, but slightly larger ; rostrum and zygomata longer ; mandible 

 larger; molars heavier ; crown of last lower molar longer. 



Color. Dorsal area well defined, grizzled dusky and yellowish ; sides 

 from nose to base of tail ochraceous, conspicuously lined with black hairs ; 

 ankle dusky posteriorly ; tail sharply bicolor, grayish brown above, 

 whitish beneath ; fore and hind feet soiled whitish. 



Remarks. Zapus alascensis is much more closely related to Z. hudsonius 

 of the northeastern United States and Canada than to Z. trinotatus of the 

 Puget Sound region. It agrees with hudsonius and differs from trinotatus 

 in the narrow braincase, small incisive foramina, and relatively small 

 under jaw. The crown of the last lower molar is longer than in either 

 hudsonius or trinotatus. 



Measurements. Type specimen: total length, 225; tail vertebrae, 139; 

 hind foot, 32. Average of 4 specimens from type locality: total length, 

 217.5; tail vertebra, 132; hind foot, 31.5. 



