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Show 1895.] THE M A M M A L S O F A D E N . 549 21. GERBILLUS (DIPODILLUS) POSCILOPS, sp. n. a-c. Lahej. 20-29. III. 95. d-g. Shaik Otbman. 2-3. IV. 95. Size medium among Gerbilles in general; trunk larger than in G. campestris; but ears, feet, and tail shorter, the feet especially bearing to the size of the head and body the proportion found in Mus rather than Gerbillus. Fur short, soft, and sleek. General colour rich fawn, rather greyer on the back, brighter on tbe sides. Face with the usual supraorbital and post-auricular white patches very prominent; white of the lips and chin ascending on the cheeks nearly to the lower eyelid. On the top of the nose a distinct black patch. Ears very small and narrow, laid forwards in a spirit-specimen they only just reach to the posterior canthus of the eye; the anterior half of their outer surfaces thinly haired, fawn, the remainder naked; a large naked patch on the sides of the head behind and below their outer bases. Under surface, whole of fore limbs, front of hind limbs, and top of feet pure white. Palms as usual in the subgenus. Soles wholly naked, granulated distally, with six pads, as in typical Dipodillus, but the two proximal pads exceedingly small. Tail short, little, if at ail, longer than the head and body ; the hairs of its upper surface brown or black, not or scarcely elongated terminally, of its sides and lower surface white. Skull strongly built, with heavy overhanging supraorbital ridges, somewhat like those of many Meriones, and forming rudimentary postorbital processes. Bullae rather large, about as in average specimens of " Hendecapleura." Molars small and delicate. Dimensions of an adult male, preserved in spirit:- Head and body 107 millim.; tail 109; hind foot 23*5; ear 11 x 7*7. Skull (of the type): basal length 26*2 ; greatest length in middle line 30*5; zygomatic breadth (c.) 17*2; nasals 11*5x3*4; interorbital breadth 5*9; tip to tip of postorbital processes 10*3; interparietal 3-3 x 6'8 ; palate length from henselion 14 ; diastema 8*5 ; palatal foramina 4-5; upper molar series 3*6; greatest oblique diameter of bullae 11. Type. Skin c. B. M . No. 95.6.1.64. This species differs so widely from all others known to us that we are unable to say what is its nearest ally. Its unusual proportions, its short ears, feet, and tail, compared with its heavy head and body, render it quite unlike the ordinary graceful Gerbilles. It will be seen from the measurements that the hind foot is actually shorter than the basal length of the skull, while in all other Gerbilles known to us it is longer. With regard to its subgenus, w e think that the characters of this and the next species render the distinction of Hendecapleura from Dipodillus exceedingly doubtful, as both present, with six posterior pads, the larger bullae characteristic of Hendecapleura. While doubtful about this point, however, w e should like to say a ,word of appreciation of Lataste's remarkable, and, w e believe, |