THE IIARRIMAN ALASKA EXPEDITION 23 



Measitremcfits. — An adult female from type locality: total length 

 188; tail vertebne 43; hind foot 23. 



MIGROTLTS ABBREV'IATUS^ FISHER! subsp. nov. 

 St. Matthew Island Vole. 



lype from St. Matthew Id., Bering Sea. No. 97976 $ ad. U. S. 



National Museimi, Biological Survey Collection. July 15, 1899. 



A. K. Fisher. Orig. no. 3189. 



Characters. — Similar to M. abbreviatus but yellow suffusion even 

 more intense, particularly on belly; nasals and rostrum (above) de- 

 cidedly longer; zygomata more strongly bowed outward; bulla; 

 broader, less pointed anteriorly, and less flattened on outer side. 



' Since the original description of Microtus abbreviatus was based on a poor 

 alcoholic specimen and does not fairly present the characters of the species, 

 I have drawn up the accompanying description from a series of adults collected 

 by me at the type locality : 



MICROTUS ABBREVIATUS Miller. 

 Hall Island Vole. 



Type from Hall Island, Bering Sea. 



Characters. — Size large; ears rather small ; tail exceedingly short, thick and 

 densely covered with long hairs ; fur long, full and soft ; appearance lemming- 

 like ; color deep yellowish gray unlike any other Microtus known to me, except 

 the closely allied form from the adjacent St. Matthew Id. 



Color. — Upperparts uniform deep yellowish gray, intimately but inconspicu- 

 ously mixed with black hairs, becoming light ochraceous buff or bright buff on the 

 sides, and darkening to grayish fulvous on head; underparts whitish, strongly 

 washed with yellowish buff; fore and hind feet whitish, washed with buffy ; tail 

 bicolor, dusky above, overlaid with long buffy hairs, buffy below. Yoiittff ; 

 upperparts yellov/ish or buffy brown ; underparts plumbeous washed with buffy 

 ochraceous. 



Cranial characters. — Skull large (largest of the Bering Sea species except in- 

 nuitus from St. Lawrence Id.) ; zygomata moderately bowed outward, their 

 outer sides parallel ; jugal only slightly if at all expanded ; frontal ' pinched 

 in ' between orbits, its muscular impressions uniting in a low ridge along 

 median line; braincase large and broad; interparietal in adults pentagonal, the 

 anterior border straight with a pointed projection on median line; the hinder 

 border produced posteriorly so as to be broadly triangular, forming two sides ; 

 bullae of moderate size, pointed anteriorly and flattened on outer side; incisive 

 foramina shortlv open anteriorly, broadly constricted posteriorly; antorbital 

 foramen without protruding anterior lip ; incisors not protruding as in innuitas : 

 molars of medium or rather large size; ;«^ with only 2 completely closed tri- 

 angles ; m^ with 5 closed triangles. 



Measurements. — Adult male: total length 170; tail vertebra; 29 ; hind foot 

 24. Average of 3 females: total length 156; tail vertebne 25 ; hind foot 23.2. 

 Skull of male adult 1 979S1 ) : total length, 30.3 ; zygomatic breadth 18 ; mastoid 

 breadth 14; nasals 8.8; molar series 7. 



