DIPODOMYS. 163 
as a geographical race or “subspecies” of the latter. I have no opportunity of 
examining a sufficient series of specimens to warrant the expression of an independent 
opinion ; but Dr. Coues’s descriptions and tables of measurement appear to be conclusive, 
and I therefore follow him in recognizing only one species of Dipodomys, varying in 
length of head and body from about 325 to 5”, and in that of tail from 5” to 7". 
The upper parts are of a darker or paler tawny brown; and the head, thighs, and tail 
are adorned with longitudinal stripes of pure white. 
1. Dipodomys phillipsi. 
Dipodomys phillipii, Gray, Ann. & Mag. Nat. Hist. vii. p. 521 (1840, descr. orig.)’. 
Dipodomys phillipsi, Coues, Proc. Philad. Ac. 1875, p. 325°; Mon. N.-Am. Rodent. p. 540°. 
Macrocolus haltecus, Wagner, Arch. f. Naturg. xii. 1, p. 176 (1846, descr. orig.)*. 
Dipodomys ordii, Woodhouse, Proc. Ac. Philad. 1853, p. 223 (descr. orig.)°; Baird, Mamm. N. Am. 
p- 410°; Rep. U.S. Mex. Bound. Surv. 1. Mamm. p: 427; Dugés, La Nat. i. p. 188°. 
Dipodomys phillipsi ordi, Coues, Proc. Ac. Philad. 1875, p. 326°; Mon. N.-Am. Rodent. p. 541°. 
Hab. Nortn America, from Washington Territory southwards ?.—Mexico 4, Sonora, 
Santa Cruz (Clark, US. Nat. Mus."), Durango (Webb, ib.”), Coahuila, Real del 
Monte (Phillips, Mus. Brit.1), San Luis and Guanajuato (Dugés 8). 
Phillips’s Pocket-Rat appears to be pretty generally distributed throughout the more 
Northern States of Mexico, Guanajuato being the most southern locality with which I 
am acquainted. Mr. Clark, of the United-States Boundary Survey, observes that in 
Sonora these Rats make large piles of loose earth on the surface of the ground, each 
of which has several entrances about the base, leading into the hollow interior’. In 
Arizona it appears to have accepted advancing civilization with greater philosophy 
than some of the higher Mammals. Dr. Coues remarks that ‘“ Since the erection of 
buildings in the interior of Arizona the Kangaroo-Rat has in great measure taken up 
its residence about them, showing the same adaptability to semi-domestication that the 
House-Mouse exhibits. Many used to live in our storehouses and granaries at Fort 
Whipple, and even brought forth their young there, in just such nooks as the common 
Mouse would select. Parturition occurs in May or June, though more than one litter 
may be produced in one season. ‘The young are for some time much darker and 
greyer than their parents. Although sullen and apparently much cowed when first 
caught, these Rats soon become familiar and make agreeable pets. I have frequently 
seen them enter my tent at night when all was still and search about for food. They 
ordinarily move on all-fours, with a motion not unlike that of a Rabbit when leisurely 
moving about. The body is alternately strongly arched and extended ; the long hind feet 
-rest on the ground to the heel, and the heavy tail trails straightly after. If frightened, 
this easy motion is changed to a succession of astonishingly vigorous leaps” *. 
* « American Naturalist,’ i. p. 396. 
Y 2 
