188 Bangs — .4 New Rock Vole from Labrador. 



eral well-marked and constant cranial and dental characters. 

 It may be known as — 



Microtus chrotorrhinus ravus * subsp. nov. 



Type from Black Bay, Labrador, rf old adult, No. 7951, coll. of E. A. 

 and O. Bangs. Collected July 15, 1898, by Ernest Doane. 



Color and pelage. — Eur longer, softer, and more like Phenacomys than 

 in M. chrotorrhinus chrotorrhinus ; all the colors paler; upper parts pale 

 grayish raw umber, somewhat darkened on back by a sprinkling of black- 

 tipped hairs ; nose and face back to eyes pale tawny ochraceous, this 

 color suffusing much of head, especially about the ears ; under parts gray, 

 extending well up on sides and gradually blending with color of upper 

 parts; feet and hands gray; tail dusky brown above, paler and grayer 

 below, sparsely haired ; whiskers black and yellowish white mixed. 



Cranial and dental characters. — The skull, compared with that of true 

 M. chrotorrhinus, is much more slender and more constricted between the 

 orbits; rostrum more slender; incisive foramina longer; audital bullae 

 flatter, less inflated, more oblong, and less round. Pattern of enamel 

 folding of molar teeth substantially the same ; molars all much smaller 

 and more delicate ; incisors more slender. 



Measurements. — The type, rf old adult; total length, 170; tail vertebrae, 

 50 ; hind foot, 22; ear from notch, 14. Averages of four adult topotypes, 

 of both sexes : total length, 159.75 ; tail vertebrae, -46; hind foot, 21.25 ;t 

 ear from notch, 12.5. .Skull (type, rf old adult) — basal length, 21.8 ; oc- 

 cipito-nasal length, 26.6; zygomatic width, 15; mastoid width, 11.6; 

 width between orbits, 3.6; length of nasals, 7.4; length of upper tooth 

 row, 6; length of mandible, 1(5.4. 



Remarks. — 1 find it very hard to express the differences in color between 

 true M. chrotorrhinus and M. c. ravus, though they are evident enough 

 when series of the two forms are laid side by side. Young examples 

 show the differences in color quite as well as do adults. 



Without a complete series from connecting localities, it seems better to 

 regard ravus merely as a subspecies of chrotorrhinus, although the rock voles 

 from Lake Edward, Quebec, are in every way inseparable from true 

 chrotorrhinus from the type locality — Mount Washington, N. H. — and 

 show no approach to the form of the coast of middle Labrador. 



* Ravus = gray-yellow. 



t The collector's measurements for foot run larger in M. c. rams than in 

 true M. chrotorrhinus. 1 can, however, detect no appreciable difference in 

 the dried skins. 



