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Show 534 MR. W. L. SCLATER ON SOME INDIAN MURID.E. [June 17, it is the external posterior, not the internal posterior, cusp missing. In Chiropodomys there are three central, three external, and generally two internal cusps, but in some specimens small traces of the third posterior cusp can be seen. The median molar in Mus consists of two central, two external, and two internal cusps; in Vandeleuria of two central, one external, and three internal; in Chiropodomys of two median, two external, and two internal cusps, with perhaps traces of the third posterior cusp. The molars of the lower jaw are much the same in Mus and Vandeleuria, the anterior consisting of six cusps in two rows bilaterally symmetrical, and the median of four cusps in two rows, also bilaterally symmetrical. In Chiropodomys the condition seems more primitive, as in addition to the cusps present in Mus and Vandeleuria there is a strong external cingulum present which seems to me to represent the true external cusps present in the upper jaws of the molar. Chiropodomys appears therefore to be, so far as the dentition is concerned, a somewhat primitive form combining the dental characters of both Mus and Vandeleuria, and in addition to that showing distinct traces of the way in which the bilaterally symmetrical molars of the lower jaw of typical Rats have been derived from a form of tooth consisting of a row of central cusps with lateral cusps such as are still found in the upper jaw. This speculation is rather supported by the condition of the dentition in Hapalomys, as will be seen below. The following are the measurements of a specimen in spirit from Cherra Punji in Assam -.-Head and body 3-35, tail 5-15, tarsus -70, arm and hand PO, ear-conch -53, muzzle to ear (skull extracted) •90. The examples of Chiropodomys gliroides in the Museum collection are from the following localities -.-Cherra Punji in Assam, Munipur, and the valley of the Sitang River in Burmah. This species has also been recorded from the Malay Peninsula (Hume coll.), Upper Burma (Doria), Borneo ( Wallace), and Java (Doria). 31. HAPALOMYS LONGICAUDATUS, Blyth, J. A. S. B. xxviii. p. 296. The specimens from which this species was described have hitherto remained, so far as I am aware, unique; they were procured by Major Berdmore in the valley of the Sitang River in Burma. The following description contains considerable additional matter to the short one published by Blyth (I. s. c.) thirty-one years aS°- ... , The fur is soft, contains no traco of spines ; it is very long, measuring about three-quarters of an inch on the back; the basal three-fourths is very dark slate-coloured, the tips a paler chestnut, with few or no traces of longer black hairs. The body beneath, including the chin and the tip of the muzzle, is white with no trace of the slate-coloured bases to the fur. The tail is very long, and resembles that of Chiropodomys in being clothed with hairs gradually increasing in length distally till |
