OCR Text |
Show 152 ON SMALL MAMMALS FROM DEMERARA. [Feb. 15, 7. HESPEROMYS (RHIPIDOMYS) SCLATERI, sp. n. (Plate XIX.) a. 2 • Maccasseema. 11/86. "I am sorry to say I cannot remember anything about the habits of this Rat; it was caught and brought to me by one of Mr. im Thurn's Indians, and of course did not live in the house." Fur short, close, very soft and velvety. General colour uniform dark ashy grey, the tips of the hairs below white or pale rufous, line of demarcation not strongly marked; bases of all the hairs slate-coloured. Hairs on both fore and hind feet, including the fingers and toes, all dark brown or black. Ears, when laid forward, reaching just to the centre of the eye ; no projection on their anterior border; their backs hairy, black. Tail long, uniformly black, thickly hairy, the hairs about 3 or 4 m m . long throughout, except just at the base, where they are shorter, and at the extreme tip, where they are 10 or 12 m m . long; the rings of scales well-marked, 15 or 16 to the centimetre. Mammse 6, one axillary and two inguinal pairs. Interdental palate-ridges 6. Foot-pads broad, smooth, rounded; soles naked, quite smooth. Skull exceedingly similar to that of H. leucodactylus, Tscb. (figured P. Z. S. 1884, pl. xliv. fig. 8), but rather longer and narrower, especially in the cranial portion, with the supraorbital edges more strongly developed, and with the incisors rather longer and heavier. Dimensions of the type, an adult female in spirit:-Head and body 133 mm., tail 172, hind foot 33, forearm and hand 39, ear, above crown, 16, head 43, muzzle to eye 18*5. Skull. Basal length 31*5, greatest breadth 19; nasals, length 12"8; length of molar series 6*4; back of incisors to front of m1 10-2; palatine foramen, length 8-0; interorbital constriction 6-3. This species, with which I am glad to connect the name of its discoverer and donor, is very closely allied, in all its essential characters, to H. (Rhipidomys) leucodactylus, Tsch.2, but that species has its fur very much the nature, colour, and texture of that of the Common Rat; while in //. sclateri the fur is wholly different to this, being in fact more like that of certain of the smaller Opossums in its soft and velvety character. In If. sclateri the colour is also darker and more uniform than in H. leucodactylus, the tail is more uniformly bushy, and the feet, both fore and hind, differ by having black-haired instead of pure white toes. The present is the first recorded occurrence of any member of the interesting Dormouse-like subgenus Rhipidomys in the region north of the Amazons and east of Colombia, and gives therefore a very important addition to tbe known range of the subgenus. Other species have been recorded from Central America, Ecuador, Peru, Bahia, and Minas Geraes, the nearest ally of H. sclateri being, as already noted, the Peruvian Li. leucodactylus, Tsch. 2 Faun. Peruana, p. 183, pl. xiii. fig. 2 (1844). |