Vol. XXIX, pp. 209-212 September 22, 1916 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



TWO NEW MAMMALS FROM SUMATRA. 

 BY MARCUS VV. LYON, Jr. 



In studying some of the collections made by Dr. W. L. 

 Abbott and presented by him to the United States National 

 Museum, I find two rats which represent forms not hitherto 

 described. They may be known as: 



Rattus vociferans tapanulius new subspecies. 



1903. Mus fremens Miller, Proc. U. S. Nat. Mas., vol. 26, p. 463, Feb- 

 ruary 3, 1903. Not Mus fremens from Sinkep Island. 



Type specimen.— ^o. 114453, U. S. Nat. Mus., skin and skull of adult 

 male, collected at Tapanuli Bay, west coast of Sumatra, February 16, 

 1902, by Dr. W. L. Abbott; original number 1538. 



Geographic distribution. — Known only from vicinity of Tapanuli and 

 Tarussan Bays, but probably having a considerable range along the west 

 coast of Sumatra. 



Diagnostic characters. — Differs from Rattus vociferans vociferans of the 

 Malay Peninsula and also of Aru Bay, Sumatra,* in being decidedly 

 duller in color, the dull zinc-orange colors of vociferans being replaced 

 by cinnamon-buff; in other respects the two forms are essentially alike. 



Color. — Upperparts and sides of head, neck and body and outerside of 

 legs, a mixture of cinnamon-buff and blackish brown; along the back 

 the two colors about equally mixed or blackish slightly in excess, along 

 sides of head, neck and body cinnamon-buff predominating. Tail dull 

 drab-brownish, slightly lighter on underside and toward tip. At center 

 of tail 7 scales per centimeter, each scale subtended by three light colored 

 hairs, about one and one-half, or one and three-quarters scales in length. 



Skull and teeth. — These show no essential differences from those of 

 Rattus vociferans vociferans. 



Measurements.— Tyipe: Head and body, 236; tail, 375; hindfoot, 47; 



• The Aru Bay specimens were identified by me as Mus fremens in 1908 (Proc. U.S. 

 Nat. Mus.. vol. 34, p. 647). I now regard them as very close if not identical with Epimye 

 vociferans. None of them are fully adult. 



3&-PR0C. Biol. Soc. Wash., Vol. XXIX, 1916. (209) 



