_Measurements._--The type and an adult female (its measurements in parentheses) yield measurements as follows: Total length, 300 (299); length of tail, 78 (83); length of hind foot, 43 (40); occipitonasal length of skull, 56.3 (55.5); basilar length, 49.3 (47.8); zygomatic breadth, 37.9 (36.5); interorbital breadth, 8.7 (8.1); greatest height of cranium, as explained above, 21.6 (20.7); least depth of rostrum, 9.2 (8.8); breadth of rostrum, 12.8 (12.7); length of nasals, 19.4 (20.0); width across mastoid processes of squamosal, 38.2 (37.1); height of occiput, 16.9 (17.3); length of maxillary tooth-row, 11.9 (11.3). _Remarks._--_Cratogeomys gymnurus atratus_ is the smallest subspecies known for the species, and is so distinct from other described subspecies, that it is difficult to select one as the closest relative. In color, _C. g. atratus_ closely resembles _C. g. inclarus_, which occurs at comparable elevations in the Sierra Nevada, but the skulls are unlike. Among named subspecies of _C. gymnurus_, the skull of _tellus_ most closely resembles that of _atratus_, and, although they differ greatly in size, _C. g. tellus_ seems to be the closest relative of _C. g. atratus_. This newly described subspecies is known only from Cerro Viejo and is probably restricted to the higher elevations on this mountain. _Specimens examined._--Seven, Top of Cerro Viejo de Cuyutlan, 19 mi. S and 9 mi. W Guadalajara. =Cratogeomys zinseri zodius= new subspecies _Type._--Male, adult, skull and skin, No. 31879 Mus. Nat. Hist., Univ. Kansas; from 13 mi. S and 15 mi. W Guadalajara, Jalisco, Mexico; obtained on February 6, 1949, by J. R. Alcorn, original No. 7747. _Range._--Known only from the type locality. _Diagnosis._--Size small (see measurements); tail short; hind foot small; upper parts Sayal Brown, underparts Pinkish Buff, hind foot whitish; skull small, narrow; outline of dorsal profile of skull concave; zygomatic breadth narrow; nasals actually short, but relatively long; width across mastoid processes of squamosal short; auditory bullae inflated; interorbital constriction narrow; maxillary teeth relatively large.