No. 1626. MAMMALS FROM HASTERN SUMATRA—LYON. 661 
but are very different from the Tupaias collected along the Siak River 
and deseribed below as new. ‘The hairs of the tail are conspicuously 
annulated, and there is no approach to the “ whitish or cream yellow ” 
tail of Tupaia ferruginea demissa Thomas from Tanjong Bringin, 
only a few miles to the southeast. 
For measurements see table, page 662. 
TUPAIA SIACA, new species. 
1905. Tupia castanea, SCHNEIDER, Zoou. Jahrb. Syst., XXIII,.p. 87. 
Type.—sSkin and skull of adult female, Cat. No. 144205, U.S.N.M., 
collected along the Little Siak River, eastern Sumatra, November 4, 
1906, by Dr. W. L. Abbott. Original number 4856. 
Diagnostic characters——A member of the Tupaia ferruginea group, 
very similar to Zupaia castanea Miller * from Pulo Bintang, differing 
mainly in having a duller colored tail, lighter colored head, and an 
indistinct dark area on the lower back. 
Color.—The color of Tupaia siaca is so much like that of 7. cas- 
tanea that no detailed description is necessary. It is throughout a 
shade lighter except on the lower back, where there is an indistinct 
dark area. The color of the back extends forward on the head to well 
between the ears in 7upaia siaca, and to well between the eyes in 7w- 
paia castanea. The tail of 7’. castanea is brighter in color than that 
of 7’. siaca and the hairs less annulated with black. The hght annu- 
lations are orange-rufous in 7’. castanea and tawny-ochraceous in 7’. 
siaca. Compared with its geographic neighbor 7. ferruginea, T. 
staca 1s everywhere “ redder ” or more chestnut throughout, most con- 
spicuously seen in the coloration of the tails and of the underparts. 
Skull and teeth—I can find no trustworthy characters to distin- 
guish between the skulls of Tuwpaia siaca, T. ferruginea, and T. cas- 
tanea. ‘Those of the latter appear to have slightly broader palates 
and those of 7. ferruginea appear a trifle shorter than in the Siak 
Tree-shrew, but these differences are so slight that-they might be 
caused by individual variations. 
Measurements —See table, page 662. 
. Specimens examined.—Three adults and four young, skins and 
skulls. 
Remarks.—Although Tupaia siaca is very similar to 7. castanea, 
yet. from a distributional point of view it seems best to regard it as 
distinct. No doubt future collections will show that it grades in with 
I. ferrugimea on Sumatra. 
*Smithsonian Miscell. Coll., XLV, November 6, 1903, p. bd. 
Proce N. M. vol. xxxiy—0O8 43 
