36 SMITHSONIAN MISCELLANEOUS COLLECTIONS [ VOL. 45 



Mus cremorivcntcr. Tail uniform brown throughout, the tip with 

 distinct brown pencil. Neither the skin of the tail nor its hairs are 

 as dark as in the related species. Feet dirty whitish, clouded with 

 brown. 



Skull and teeth. — The skull resembles that of Mus cremoriventer,'^ 

 but is slightly larger ; the rostrum is deeper, the incisive foramina 

 are longer, and the audital bullae are less globular. Mandible more 

 robust than in the related species, and concavity between condyle and 

 angular process not as deep. Teeth as in Mus cremoriventer, but 

 slightly larger throughout. 



Measurements. — Total length, 310 (317) f head and body, 125 

 (146) ; tail vertebrae, 185 (171) ; pencil, 5 (8) ; hind foot, 28.8 

 (30?) ; hind foot without claws, 27 (28.5?) ; ear from meatus, 17 

 (17) ; ear from crown, 13.6 (13) ; skull, greatest length, 35 (34) ; 

 zygomatic breadth, 16 (15.4) ; length of nasals, 13 (11.8) ; depth of 

 rostrum behind incisors, 7 (6) ; length of incisive foramen, 6.4 (5.6). 



Specimens examined. — One, the type. 



Remarks. — While the skull, teeth, and unicolor tail show that this 

 rat is closely related to Mus cremoriventer, the conspicuous appear- 

 ance at the surface of the spines in the fur of back and sides gives 

 the animal a strong superficial resemblance to the members of the 

 surifer group. That this peculiarity is not due to moult is shown 

 by the fresh, unabraded condition of the fur. Not only are the soft 

 hairs less abundant than in Mus cremoriventer, but the spines are 

 distinctly larger. This difference is most noticeable on the back 

 and sides, but is also apparent on the underparts, particularly in 

 region between and just behind front legs. 



MUS LUTEOLUS sp. nov. 



Type. — Adult female (skin and skull). No. 104,276, United States 

 National Museum. Collected on St. Matthew Island, Mergui 

 Archipelago, January 15, 1900, by Dr. W. L. Abbott. Original num- 

 ber, 226. 



Characters. — A small member of the rajah-surifer group, re- 

 sembling Mus Havidulus of Pulo Lankawi, but with tawny element in 

 color distinctly less yellow. 



Color. — Ground color of back and sides bufif, almost exactly simi- 

 lar to that of Ridgway, very uniform throughout, though a little 

 more yellow on shoulders and neck. Back thickly sprinkled with 

 black-tipped spines, but the black is nowhere in excess of the bufif, 



' Proc. Biol. Soc. Washington, xiii, pi. v, fig. 2, April 21, 1900. 



^ Measurements in parenthesis are those of the type of Mus cremoriventer. 



