| OCR Text |
552 COL. YERBURY AND MR. O. THOMAS ON [June 18, 24. MERIONES REX, sp. n. a-g. Seven specimens, d 2 • Lahej. 6-10. III. 95. Most closely allied to M. shawi, Duv. & Ler., which ranges from Algeria through Tunis and Egypt as far as the Sinaitic Peninsula. Size larger, form stouter and heavier. Fur short, poor and rather harsh, very different to the beautiful fur of M. shawi. General colour dirty fulvous brown above, and this colour, at least in the old specimens, extends all over the underside as well; in younger specimens, however, the underside is whitish as usual. Ears much as in M. shawi, but rather more thinly haired, and the whitish spot behind their outer bases less sharply defined. Hands as in M. shawi, the usual two large wrist-pads present. Feet very large and heavy ; upper surface of metatarsals with a slight but distinct blackish suffusion ; digits dull whitish; soles almost or wholly naked, the few minute hairs not hiding in any way the usual Meriones-structure of the skin and pads. Tail long, thick, cylindrical, uniform grizzled fawn above and below throughout, except that the hairs on the top of the terminal two inches are lengthened to form a crest, which varies in colour from black to brown. Skull-differences are in this genus very difficult of description, owing to the great variation that takes place with age, so that it is always difficult to find specimens which may be properly compared with each other, without disturbance by the factor of age. However, among 16 skulls in the Museum collection referred with more or less certainty to M. shaivi, there are none so large as that of the type of M. rex, none have such long and narrow interparietals, or have their auditory meatus so little swollen anteriorly. The bullae are, if anything, slightly smaller in the new form than in M. shaivi, and show therefore no approach to the huge bullae of the eryihrurus group. Dimensions of the type, an old male in spirit:- Head and body 183 millim.; tail 200; hind foot 41*5; ear 19-5. Skull: basal length 41-2; greatest length in middle line 4 8; greatest breadth 27-5; nasals 19-6 x 5 ; interorbital breadth 8*5; tip to tip of postorbital processes 16; interparietal 5*6 x 8-7; palate, length from hensebon 21-7; diastema 12-6 ; anterior palatine foramina 8-6 ; distance from hinder angle of zygoma to nearest point of wall of meatus 2*1. Type. In spirit. B. M . N o . 94.6.1.30. This fine species, nearly or quite the largest of the genus, differs from every known Meriones in its practically naked soles, its dirty-coloured belly, and its darkened metatarsi. The only species for which it could be mistaken is M. shawi, but, besides the differences just mentioned, it is larger than that animal, and has a decidedly longer tail. Of other Arabian species known, it may be mentioned that M. crassus, Sund., from Sinai, quite clearly belongs to the eryihrurus group, with large bullae, while M. melanurus, Riipp., as |
