Bailey (N. Amer. Fauna, 39:58, November 15, 1915) referred three specimens from San Antonio, Baja California, to _Thomomys bottae nigricans_. These specimens have not, to our knowledge, been re-examined subsequently, although the current taxonomic treatment of the pocket gophers of Baja California by Huey (Trans. San Diego Soc. Nat. Hist., 10(4):245-268, 1 map, August 31, 1945) excludes _T. b. nigricans_ from the area of San Antonio. The pertinent specimens are probably Nos. 10810-10812 in the Chicago Natural History Museum. We have examined the specimens and, using the comparative materials listed under the account of _T. b. siccovallis_, find them to be intermediate in most characters between _T. b. aphrastus_ and _T. b. martirensis_. Because they more nearly resemble _T. b. aphrastus_ in the weakly-spreading zygomatic arches, we refer the specimens from San Antonio to that subspecies.
When Huey (Trans. San Diego Soc. Nat. Hist., 10:256, August 31, 1945) named _Thomomys bottae jojobae_ from Sangre de Cristo, Baja California, México, he made no mention of a specimen that Bailey (N. Amer. Fauna, 39:58, November 15, 1915) identified as _Thomomys bottae nigricans_ from La Huerta, which place is approximately eight miles northwest of Sangre de Cristo. From a geographic standpoint, it seemed unlikely that the specimen from La Huerta would be referable to _T. b. nigricans_. Examination of the specimen (138752 BS) proves it to differ from topotypes of _T. b. nigricans_ and to agree with _T. b. jojobae_ in richer, more rufescent color, especially ventrally, and smaller, slenderer, more delicate skull. The specimen is therefore tentatively referred to _Thomomys bottae jojobae_. We have not, however, compared it with specimens of _Thomomys bottae juarezensis_, a subspecies the range of which lies to the east on the summit of the Sierra Juárez.
~Thomomys bottae martirensis~ J. A. Allen
Bailey (N. Amer. Fauna, 39:58, November 15, 1915) referred pocket gophers from Piñon on the west slope of the San Pedro Mártir Mountains, Baja California, to the subspecies _Thomomys bottae nigricans_. The subspecific identity of these animals has now been reinvestigated subsequently, although the locality whence they were obtained is far removed from what is now thought to be the geographic range of _T. b. nigricans_; further, several other subspecies are known to occur in the intervening area. We have examined the available material from Piñon (13853-13855 BS) and find the specimens to agree with _Thomomys bottae martirensis_ and to differ from _T. b. nigricans_ in lighter color, larger, more ridged and angular skull; proportionately greater mastoidal breadth; narrower occipital shelf; more ventrally produced alveolar ramus of the maxillae; and deeply concave posterior border of the temporal root of the zygomatic arch. These specimens thus constitute the northernmost record of _T. b. martirensis_ known to us.