14 Bulletin American Museitm of Natural History. [Vol. XII, 



base of ear ; nose and edges of cheek pouches blackish. Below strongly washed 

 with reddish fulvous, the hairs plumbeous for the greater part of their length ; 

 inside of cheek pouches and anal region white. Tail and upper surface of feet 

 whitish or grayish white, the tail thinly haired. 



Total length (collector's measurements) of type, 225 mm. ; tail, 61 ; hind 

 foot, 30. Three specimens (2 $ $ , I ? ) measure : Total length, 216 (207-225) \ 

 tail, 62 (61-63) J hind foot, 30 (28-31). 



Type, No. 415, collection of W. W. Price, $ ad. Collected by D. Coolidge, 

 in Sierra Laguna (altitude 7000 feet), Lower California, July 10, 1896. (Type 

 in British Museum. 1 ) 



For the opportunity of examining these specimens I am in- 

 debted to the kindness of Mr. Oldfield Thomas, who, in sending 

 them with other Lower California and Mexican material for 

 determination, thus comments on their relationship to T.fulvus 

 anitcz : " Presuming that all the Lower California Thomomys were 

 the same I had not sorted them by localities, but on doing so for 

 registration it comes out at once that the Sierra Laguna speci- 

 mens are strikingly darker in color than the Santa Anita and 

 San Jose del Cabo ones, so much darker that they must evi- 

 dently be looked upon as distinct. The Sierra Laguna specimens 

 come from an altitude of 7000 feet, the Santa Anita and San Jose" 

 ones from near the sea level." He adds : " I send 3 speci- 

 mens, the brightest and lightest of 12. . . . No. 415 [here taken 

 as the type] is about the average color, though several are darker, 

 and one quite blackish. The Santa Anita specimens are all 

 identical, and can be distinguished at a glance from those from 

 Sierra Laguna." 



This form is darker and much less gray than my T.fulvus 

 martirensis, from the San Pedro Martir Mountains of Lower 

 California, and also very much smaller. The question of whether 

 these two mountain forms should not be treated as specifically 

 distinct, not only from each other but from T.fulvus, must be 

 left in abeyance, owing to the absence of proper material to 

 show their relationships. 



1 I take this opportunity to correct an error in the introduction to my paper (this Bull., 

 Vol. X, 1898, p. 143) published last year, in which several species were described from material 

 kindly submitted by Mr. Oldfield Thomas for determination. In the "set of duplicates" 

 retained by this Museum, the types of the new species were not included, as there stated, but 

 were all returned to the British Museum. 



