Descriptions of Five New Rodents. 223 



Peromyscus sitkensis sp. nov. 



Tiipe from Sitka, Alaska. No. ToSOi), cj^ a<l. U. S. Nat. IMns., Biolog- 

 ical Survey Coll. Collected July :W, 1S95, by C. P. Streator. Original 

 No. 4720. 



General cliantclerx. — Size very large — inucli the largest of the species 

 occiirring north of INIexieo except P. cnHfornicHS, 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, l^ecoming russet posteriorly on back, rump, 

 and sides; ring round eye (l)roadest 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. 



Cr(uiial characters. — Skull large ; braincase rather flat; rostrum greatly 

 elongated; pter3'goid foss;e unusually developed. Contrasted with the 

 skull of P. calif ornicus, 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 califor)ii.cus is mucli the larger animal. 



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

 hind foot, 26. Average of 20 specimens from tyi)e locality : total length, 

 218; tail vertebrje, 111.6; hind foot, 26.2. Cranial ineasiirenienfs : total 

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

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



lieniarks. — -Apparently Peromyscus sitkensis is related to P. macrorhinus 

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

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

 much longer nasal bones. 



Zapus hudsonius alascensis subsp. nov. 



Type from Yakutat Bay, Alaska. No. 7.3584, (^ ad. U. S. Nat. Mus., 

 Biological Survey Coll. Collected July 5, 18!)o, l)y C. P. Streator. Orig- 

 inal No. 4fi()0. 



General cJiaracters. — 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 deflned, 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 beneatli ; f<jre 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. trinolatus of the 

 Puget Sound region. It agrees with liudsonius and differs from trinotatas 

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

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

 hiulsonius or trinotatus. 



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

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

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



