162 Univt rsity of California Publications in Zoology [Vol. 10 



buff shafts, and black tips. The measurements of black tip were 

 made by ocular micrometer on hairs of the second type only. 



In the frequency curve for black tipping of the hairs, the 

 mode of neglectus, while different from that of longimembris, is 

 seen to fall within the normal range of variation of the latter. 

 The curve does not, however, adequately show the difference in 

 pigmentation, for the following reasons: it does not record (a) 

 the different density of pigmenl in the black tips of the hairs 

 in the two subspecies; nor (b) different width of the black 

 tipping, for in many instances the tip was not solidly black, 

 but had rather a line of black upon it; nor (c) the different 

 proportions of the two types of hairs, namely those having the 

 shafts solidly pigmented from base to tip, and those having tips 

 only black. 



NOMENCLATURAL HISTORY 



Apparently no specific name already given to western pocket- 

 mice of this subgenus is available for the new subspecies. The 

 name Perognathus parvus (Peale) formerly applied to the San 

 Joaquin form now regarded as Perognathus I. longimembris, has 

 been definitely shown to lie correctly assigned to the much larger 

 species taken in Oregon, probably in the neighborhood of The 

 Dalles. 1a the Wilkes Exploring Expedition (see C. H. Merriam, 

 1889, p. 3, and Osgood, 1900, p. 35). The following authors 

 have referred San Joaquin Valley specimens to Perognathus 

 parvus: Baird i1N-">7. p. 425), specimen from Kings River, 

 California; Coues (1875, pp. 303-305) based the name on Baird 's 

 Kings River specimen ami dissected an alcoholic specimen from 

 Fort Te.jon; True (1882, p. 474) discussed Baird 's parvus and 

 published data on additional specimens from Fresno in the San 

 Joaquin Valley. Fours' (1875, p. :i<F>> provisional name for 

 the race exemplified by his specimen from Fort Te.jon, namely 

 longimembris, must therefore stand (see Osgood, 1900, p. 34) for 

 the darker subspecies of the San Joaquin Valley. 



Osgood (1900, p. 34) based his description of Perognathus 

 I. longimembris on specimens from Fresno, the type locality of 

 inornatus C. II. Merriam. The type of longimembris, from Fort 

 Te.jon. is said to be immature, but is stated to show the narrow 



