Merriam's arrangement of _evotis_ as a subspecies of _crawfordi_ has been followed by subsequent workers, mostly, we suppose, because additional material of undoubted _evotis_ has not until now been available. Comparisons of our four specimens with specimens (from Jalisco, Sinaloa and Tamaulipas) and published descriptions and measurements (see especially Hoffmeister and Goodpaster, 1954:46-47, 51) of _crawfordi_ reveal that _evotis_ has a longer body and hind foot than _crawfordi_ but a relatively (sometimes actually) shorter tail and ear, and a distinctly larger, heavier skull (see Table 1). The upper parts of our specimens average pale brownish gray and are paler, not darker, than the upper parts of _crawfordi_. But, all of the latter were obtained in the warm months of the year except one November-taken individual from El Fuerte, Sinaloa, the dorsal pelage of which approaches in color that of the darkest of the _evotis_. The pelage of both kinds probably is paler in winter than in summer and may be indistinguishable in the same season. Ventrally, all four _evotis_ are grayish white, faintly to moderately tinged with brownish buff. _Notiosorex evotis_ differs cranially from _Notiosorex crawfordi_ as follows: larger (see measurements); mesopterygoid fossa squared rather than broadly U-shaped anteriorly; rounded process on maxillary at posterior border of infraorbital canal well developed (faint or lacking in _crawfordi_); occipital condyles smaller and, in lateral view, elevated above basal plane of skull; upper molars slightly more crowded in occlusal view. These differences, although admittedly slight, appear to be constant in the specimens we have seen, but ought to be used cautiously owing to the small samples studied. Shrews of the genus _Notiosorex_ have been reported twice previously from localities in west-central México, other than from Mazatlán, as follows: 21 mi. SW Guadalajara (remains from owl pellets) and 13 mi. S, 15 mi. W Guadalajara, Jalisco, by Twente and Baker (1951:120-121); and Cerrito Loco, 2 mi. E La Palma, Michoacán (remains from owl pellets), by Baker and Alcorn (1953:116). The remains were referred to _evotis_ on geographic grounds in one instance and were so referred inferentially in the other. Examination of the specimens upon which these reports were based reveals that all are _crawfordi_ on the basis of characters previously cited. As a result, _N. evotis_ is known only from the type locality at Mazatlán, whereas _N. crawfordi_ is widely distributed on the Mexican Plateau as far south as Jalisco and northern Michoacán, and occurs on the west side of the Sierra Occidental as far south as northern Sinaloa.