22o Field Columbian Museum — Zoology, Vol. III. 



hills of the San Pedro Martir range. It is darker and grayer than 

 T.fulvus; indeed, in certain seasons, as in the one described above, 

 the pelage is a beautiful lavender-gray. The sixteen specimens 

 exhibit a considerable diversity of coloring, a number being in 

 process of change from the gray to the darker hue and two from San 

 Antonio are very dark with a great many black hairs mixed with the 

 lighter ones. With the exception of the short nasals the skulls do 

 not show any particular characters not seen in those of T. mar- 

 tirensis, but the general hue of the pelage is much darker, and of 

 quite a different shade from that usually seen in T. fulvus or T. 

 bottce. 



FAM. HETEROMYID/E. 



SUBFAM. DlPIDOMYIN^;. 



DIPODOMYS. 



Dipodomys merriami simiolus. 



Dipodomys merriami simiolus. Rhoads, Proc. Acad. Nat. Scien., 

 Phil., 1893, p. 410, Elliot, Syn. N. Am. Mamm., 1901, p. 234. 



10 Specimens: 1 Canon Esperanza, San Pedro Martir Mts.; 9 

 San Felipe, Gulf of California. 



At Canon Esperanza this race was common on the sandy plains, 

 but rare near the base of the mountains, "but at San Felipe Bay it 

 was abundant, and the burrows were usually placed beneath bushes, 

 and they were not found in colonies as frequently as was the next 

 species." 



Dipodomys deserti. 



Dipodomys deserti. Steph., Am. Nat., 1887, P> 4 2 > PI- v -» Elliot, 

 Syn. N. Am. Mamm., 1901, p. 235. 



11 Specimens, San Felipe, Gulf of California. 



"This kangaroo rat," writes Mr. Heller, "was one of the most 

 abundant mammals at San Felipe Bay. Its burrows were seen 

 everywhere throughout the desert, where they were usually found in 

 colonies of from three or four to a dozen or more." 



PERODIPUS. 



Perodipus agilis. 



Perodipus agilis. Gambel, Proc. Acad. Nat. Scien. Phila., 1848, 

 p. 77, Elliot, Syn. N. Am. Mamm., 1901, p. 236. 



27 Examples: 8 Ensenada, 5 San Tomas, 1 Las Eucinas, 3 Trin- 



