MAMMALS OF THE NATUNA ISLANDS II9 



Remarks. — While the two specimens agree in all essential characters 

 they differ in numerous minor details. The skin from Pulo Lingung 

 is somewhat darker than the type, but the difference is due to the shade 

 of the brown wash, not to any extension of the black. The skull of 

 this specimen is more rounded posteriorly than that of the type, and the 

 rostrum is shorter. Both specimens show conclusively that their rela- 

 tionships are with the Sus cristatus of the Malay Peninsula and not 

 with the S. longirostris of Borneo, a case which finds an exact par- 

 allel in the giant squirrels. 



MUS INTEGER sp. nov. 



7>/^.— Adult male (skin and skull) No. 104837 U. S. National Mu- 

 seum. Collected on Sirhassen Island, South Natunas, June 7, 1900. 

 Original number 455. 



Characters. — A large robust species with coarse but not spinous 

 fur. Relationships with Mus validus Miller, from Trong, Lower 

 Siam, and Mus mulleri Jentink from Sumatra. Differs from the 

 former in smaller size and in the absence of the anterior outer tubercle 

 of the last upper molar, and from the latter in larger size, and yellowish 

 brown (not white) underparts. 



Color. — Back and sides a fine grizzle of black and dull ochraceous 

 (the exact shade intermediate between the ochraceous and ochraceous- 

 buff of Ridgway), the two colors nearly equally mixed on back, but the 

 ochraceous in excess on sides. Underparts and inner surface of legs 

 buff. An ill defined drab-gray median line from throat to pubic region. 

 Head darker and more glossy than back, the cheeks distinctly washed 

 with gray. Lips and chin drab-gray. Feet an indefinite brown, 

 darker on metapodials. Ears essentially naked, dark brown. Tail 

 dark brown throughout. Underfur gray (Ridgway, pi. 11, No. 8), be- 

 coming paler on under parts where it fades irregularly into the general 

 buff. 



jTur. — The fur is exactly as in Mus validus^ that is the grooved 

 bristles are so slender that their true nature is not apparent without use 

 of lens. On middle of back the mass of the fur is about 17 mm. in 

 length, the long terete hairs scattered through it reaching about 30 mm. 

 On rump the fur is longer but not conspicuously so, and there is no 

 noticeable increase in length or abundance of the terete black hairs. 



Tail., feet and mamfuce. — Tail slightly more coarsely scaled than in 

 Mus validus; 9 rings to the centimeter at middle. Hairs scarcely 

 noticeable except toward tip, where they somewhat exceed the breadth 

 of the rings. 



