1913] Grinnell-Swarth : Birds and Mammals of San Jacinto 349 



We had anticipated finding Microtus mordax, or some related 

 form, at least, at the upper elevations; but all the Microtus 

 secured, as above specified, are unequivocally referable to the 

 californicus group. In the San Bernardino Mountains, a repre- 

 sentative of the mordax group is present in the Boreal zone, and 

 californicus, also, is present but occupies a lower belt (up to 

 7500 feet altitude), the ranges of the two overlapping ;it several 

 points (see Grrinnell, 1908, p. 148). In the San Jacinto Moun- 

 tains, mordax appears to be absenl altogether, while californicus 

 ranges up well into Boreal. This bespeaks ;i notable hardihood 

 on the part of this latter species, greater than is suggested by 

 its lower range elsewhere. It is possible that the existence of 

 another Microtine representative in the Boreal zone elsewhere 

 is the chief factor preventing invasion of californicus upward. 



The San Jacinto skins of californicus, like those from else- 

 where in extreme southern California, show a distinct mixture 

 of reddish hairs in the dorsal pelage, giving a rusty effect as 

 compared with californicus from the central portion of the .slate. 

 This tendency is apparently in the direction of the character 

 ascribed to Elliot's Microtus c. hyperythrus, described from 

 northern Lower California. The peculiarity does not seem to 

 be developed in the San Jacinto animals to a degree to merit 

 taxonomic recognition. 



Thomomys perpallidus C. II. Merriam 

 Balm Springs Gopher 



Balm Springs, the type locality of this gopher, was visited 

 in February. 1912, for the special purpose of obtaining an ade- 

 quate series. Forty specimens were secured, nos. 16485-16524. 

 Two other examples are in the Museum (nos. 4635, 4(i72). taken 

 in the same locality in December, 1903. 



The gophers were trapped only ahum' the ditch leading down 

 from Tahquitz Canon to the village, and in irrigated pastures 

 and gardens in the town itself. The animals were actively 

 throwing up earth only where the ground was moist. In both 

 situations there was plenty of newly growing vegetation, par- 

 ticularly Bermuda grass, the root-stalks of which seem to be 

 especially sought for food. Old workings were observed on 



