[NO. 319. GERBILLUS CRYPTORHINUS.]
The Lobe-nosed Jerboa-Rat.
HABITAT.—Yarkand.
DESCRIPTION.—after Mr. Blanford, who first described and named the species: "Colour above sandy rufescent, some specimens rather more rufous than others; below white, the two colours sharply divided on the sides; cheeks pale; supercilia whitish; feet white; tail above rather more rufous than the back, paler and occasionally whitish below, becoming dark brown or blackish above near the end, and with the slight tuft of longer hairs at the end of the same dark colour; fur soft and glossy, about half an inch long in the middle of the back, all the basal portion being at least three-quarters of the length, dark ashy; the terminal portion pale yellow brown to pale rufous, with numerous longer hairs with black tips mixed; on the under surface the hairs are white throughout; on the tail the hair is rather short, coarse, and close together; there are a very few longer black tips mixed, but scarcely enough to produce an effect in the general colour.
"The ears are oval and of moderate length; densely clad with brown hairs on the anterior portion of the outer surface, and with a fringe of longer hairs on the anterior margin; the posterior portion of the external surface is nearly naked, except near the margin, and the anterior portion of the inner surface is completely destitute of hair, but the inner surface is more hairy near the hinder margin. The whiskers are very numerous, the longest slightly exceeding the head; the uppermost behind being black, all the rest white; all are mixed at the base with long hairs, which cover the side of the nose; soles of the fore-feet with scattered white hairs, but nearly naked; those of the hind-feet densely covered with hair everywhere except at the extreme tips of the toes and at the heel.
"Mammæ, eight—four pectoral and four inguinal, as usual in the genus.
"The most remarkable character of these species is the presence at the end of the snout of a semi-circular lobe, which forms a flap completely covering the openings of the nostrils. This lobe can, of course, only be well seen in the specimens preserved in spirit. In the dried skin its presence can sometimes be detected, but not always. In the only spirit specimen, an adult female, the flap measures about 0·3 inch in breadth, and is barely an eighth of an inch long.
"It is hairy both outside and inside, the hairs being very short and rather scattered inside; the surface below the nostrils covered by the flap is also hairy. The use of this lobe is evidently to keep out sand and dust from the air passages" (W. T. Blanford's 'Mammalia of the Second Yarkand Mission,' p. 56).
SIZE.—Head and body, about 5½ inches; tail, 5 inches; length of fore-foot, 0·5 inch; hind-foot, 1·4 inch.
The peculiarity of the lobe, which was first detected by Mr. Oscar Fraser in removing a skull from a spirit specimen, distinguishes this species from the other Asiatic forms. There is also a peculiarity in the skull noticed by Mr. Blanford, which is that the lachrymal process, instead of being anchylosed to the adjoining bones, as in others of the genus, is free, and this species is therefore distinguished from the one most resembling it, G. unguiculatus from Chinese Mongolia, in which the lachrymal process is united to the frontal.
[NO. 320. GERBILLUS ERYTHRURUS.]
The Red-tailed Jerboa-Rat.