E. Raymond Hall

“ Comparisons.—From topotypes of its nearest relative, Microtus mexicanus phaeus Merriam, salvus differs as follows: Tail shorter; pelage with slightly more buffy (reddish) pigment which, nevertheless, is of a lighter tint; premaxillary borders of nasals straight rather than concave; superior outline of skull more nearly straight (less convex) ; inferior border of rostrum more nearly straight (less concave distally) ; palatal fossae uniformly shallower.
Comparison with M. m. fundatus is made in the account of that subspecies. ”

“ Relying on Bailey's (N. Amer. Fauna, 17:55, 1900) description of Microtus fulviventer, fundatus differs in much larger tympanic bullae.
Remarks.—The series of 59 specimens includes individuals of several ages of both sexes. This has been a great advantage in making comparisons with individuals of geographically adjoining subspecies since individuals of the same age and sex could be compared. ”

“ No. 100637, Univ. California Mus. Vert. Zool.; 31⁄2 mi. S Pátzcuaro, 7,900 ft., Michoacán, México; March 9, 1943; obtained by E. R. Hall, original no. 5882.
Range.—Known only from the vicinity of the type locality. ”