356 University of California Publications in Zoology [Vol. 10 



latter half of May, at the several localities, the earliest noted 

 another chapter (see pp. 388-392). 



Dipodomys merriami parvus Rhoads 

 San Bernardino Kangaroo Rat 



This form was found by us only at Vallevista, 1800 feet, at 

 the Pacific base of the mountains. Here it was represented in 

 fair abundance in tracts of brush on the level floor of the San 

 Jacinto Valley. Eleven specimens were secured (nos. 2258- 

 2267, 9364 ) . August 30 to September 3. Five of these are young- 

 iif-tlie -year, the remainder fully adult. All of these appear to be 

 identical with practical topotypes of parvus from Cajon Wash, 

 near San Bernardino. 



Since there appears to be no adequate description of this 

 species in literature, we offer the following account. In color. 

 purr us is distinctly grayer, less ochraceous than simiolus; in the 

 former the tint of the colored parts of the hairs dorsally is clay 

 color, in the latter ochraceous buff. In parvus the color is much 

 more obscured by the greater amount of dusky tipping to the 

 hairs; this obscuration is greatest in the mid-dorsal region, leav- 

 ing the sides more purely clay color. In parvus the dark mark- 

 ings generally are heavier and hence better defined; the facial 

 markings, soles of hind feet, and tail stripes and tuft are dis- 

 tinctly sooty. The young of the two races show comparable 

 differences, save that in the first pelage of parvus the facial 

 markings are obsolete as in simiolus. 



The accompanying table of measurements shows that in 

 parvus and simiolus body length is the same, but. that parvus has 

 slightly shorter tail and hind foot. However, the ranges in 

 dimensions overlap to such a degree that measurements indi- 

 vidually have no diagnostic value. It is interesting to note that 

 the range of variation in the size of the two forms appears to 

 be about the same. 



As to cranial characters, parvus has slightly the smaller skull; 

 the audital bullae are distinctly smaller, and the brain case 

 higher, more bulging on top. The latter two are obviously cor- 

 related characters and there are doubtless other dependent 

 features. 



