Page:Notes on the Slow Lemurs.pdf/8

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Distribution.—Probably the mountainous regions of Sumatra, known only from the the type locality, Batu Sangkar, Tanah Datar, Padangsche Bovenland, Sumatra.

Diagnostic characters.—Similar to Nycticebus malaianus, but slightly larger, with audital and mastoid bullaebullæ [sic] not smooth, rounded and inflated, but irregularly grooved instead.

Color..—Of the two specimens examined one has a general wood-brown effect above with considerable frosting, and the other a very dull ochraceous. Dorsal stripe extends whole length of back but indistinct posteriorly, dark brown in color. Head markings dull russet, considerably obscured by grayish tips to hair. Underparts dirty buffy, slaty bases of hairs showing through.

Skull and teeth.—Skull nearly as large as that of Nycticebus coucang. Temporal ridges forming a crest in old age. Upper incisors, four in the young, two in adults. Mastoid and audital bullæ irregularly wrinkled.

Measurements.—See table, page 537.

Specimens examined.—Two, the type and a paratype.

Remarks.—This species appears to be a larger mountainous form of Nycticebus malaianus, from which it seems to differ but slightly.

Distribution.—Island of Bunguran, North Natuna Islands.

Diagnostic characters.—Similar to Nycticebus malaianus, but darker in color and with dusky hands, feet, and ears.

Color.—Upper parts generally similar to Ridgway’s russet, a slight amount of frosting. Dorsal stripe extending entire length of back, but indistinct on rump, broadest over shoulders, dark brown, almost blackish in places; on crown of head and face markings, like Ridgway’s burnt umber, but lighter; rings about eyes almost black. Underparts generally dark ochraceous buff except on throat which is grayish. Upper surfaces of hands and feet irregularly blotched with blackish, ears with brownish black.

Skull and teeth.—The skull of Nyctiebus natunæ does not differ appreciably from skulls of N. malaianus. The interorbital constriction is not so pronounced and the mastoid bullæ are a little less inflated. Four incisors are present in the upper jaw.

Measurements.—See table, page 537.

Specimens examined.—One, the type, Cat. No. 104599, U. S. N. M.

Remarks.—This species appears as a slightly differentiated form of