MAMMALS COLLECTED BY DR. W. L. ARBOTT 



209 



tail is defective and the pelage is so worn that the inidcrfur appears 

 at the surface in irregular patches. Under the circumstances any 

 exact determination is impossible. In its whitish belly and in the 

 form of the skull the animal agrees with Mzis vociferans and shows 

 no approach toward the characters of M. strcpitans. 



MUS TIOMANICUS sp. nov. 



Type. — Adult male (skin and skull). No. 101763 United States 

 National' Museum. From Tioman Island. Collected October 4, 

 1899. 



Characters. — In size, proportions, quality of fur, and cranial char- 

 acters similar to the form of ]\Ius ' alexaizdrimts ' occurring in Trong, 

 Lower Siara, but color throughout much darker. 



Color. — Dorsal surface raw umber heavily and finely grizzled with 

 blackish brown, the fur faintly lustrous in certain lights. Sides and 

 cheeks slightly paler than back and much less profusely sprinkled with 

 dark hairs. Ventral surface dull white, the chin and throat tinged 

 with cream-buff, the chest faintly washed with brown. Throughout 

 the pelage except on chin and throat the hairs are light slate-gray at 

 base. Outer surface of front legs drab-gray. Inner surface of all 

 four legs like belly. Muzzle and dorsal surface of feet dull sepia. 

 Tail uniform dark brown throughout. 



Skull and teeth. — In both cranial and dental characters this species 

 is practically identical with the form of Miis alexandrinus found in 



Fig. II. a Mus tiomanictis. b M. siantaniciis. c M. tamhelanicus.' 

 Natural size. 



Trong, Lower Siam. The skull as a whole is, however, slightly more 

 elongate than in the mainland animal, the difference most noticeable 



