42 Description of a New Species of Dipodomys. [Jan. 
learned by a study of the figures (Plate IV.) with the accompany- 
ing explanations. We could now pass on to the subject of fertili- 
zation did we not have connected with this phenomena another 
series of phenomena that can be understood only by reference to 
the facts of “cell division,” to which we next direct our attention. 
(To be continued.) 
DESCRIPTION OF A NEW SPECIES OF DIPOD- 
OMYS, WITH SOME ACCOUNT OF ITS 
HABITS. 
BY F. STEPHENS. 
Dipodomys deserti STEPHENS, n. s. Desert Pocket-Rat. 
ARGEST known species of the genus. Length, head and 
body, 5.2 inches; tail vertebræ, 7.7 inches; hind foot, in- 
cluding claw, 1.9 inches. Color above pale yellowish brown, fur 
plumbeous at base, showing through the tips enough to give an 
ashy tinge. Below, white. Fore legs from elbow, and hind legs, 
in front, from knee, white. Tail, at base, on sides, below, and the 
tip, white; above, pale brown, becoming plumbeous towards the 
white tip. Indistinct white spot over the eye, another behind 
the ear, which extends across the shoulder to the white under- ` 
parts. Indistinct white band across the hips. Indistinct darker 
spot at base of whiskers. Soles of hind feet nearly white. Type 
No. 314. Female, June 29, 1886. Mojave River, Cal. Deposited 
in the National Museum. 
Habitat, Mojave and Colorado Desert regions of Southeastern 
California. 
COMPARISON OF THE SPECIES. 
. Dipodomys deserti. Dipodomys phillipsi. 
Size large. Size small. 
Color pale, markings comparatively in- Color dark, markings distinct. 
distinct 
Eyes TEES ely large. Eyes very lar 
Soles of hind feet white in the young, Soles of feet dark brown (same color as 
indistinctly brownish in the adults, per- upper surface of tail). 
haps due to soiling. 
Spot at base of saree merely darker Spot at base of whiskers nearly black. 
than surrounding 
Masti region coro nate. Mastoid regi paratively moderately 
i Aitaa 
