38 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vOL. 45 



MUS BENTINCANUS sp. nov. 



Type. — Adult female (skin and skull), No. 104,269, United States 

 National Museum. Collected on Bentinck Island, Mergui Archi- 

 pelago, March 11, 1900, by Dr. W. L. Abbott. Original number, 



348. ^ 



Characters. — A rather large member of the rajah-surifer group, 

 much resembling Mus butangensis, but color of back less strongly 

 suffused with yellow. 



Color. — The color is so similar to that of Mus umhridorsiim as to 

 need no special description. The black of the back, however, shows 

 very little tendency toward the formation of a dorsal stripe. 



Measurements. — Measurements of type : total length, 385 ; head 

 and body, 205; tail, 180; hind foot, 42 (40) ; skull, greatest length, 

 47 ; zygomatic breadth, 22. 



Specimens examined. — Eight (two skulls without skins), all from 

 Bentinck Island. 



Remarks. — This race is distinguishable from Mus butangensis by 

 its lighter color, and from its relatives of the Mergui Archipelago 

 by its large size combined with the absence of a throat band. 



MUS CASENSIS sp. nov. 



Type. — Adult male (skin and skull), No. 104,249, United States 

 National Museum. Collected on Chance Island, Mergui Archipel- 

 ago, December 28, 1899, by Dr. W. L. Abbott. Original number, 

 188. ; ; 



Characters. — Similar to Mus butangensis, but with well developed 

 throat band. 



Coir. — The color so closely resembles that of Mus butangensis 

 as to require no detailed description.^ As in this form the ground 

 tint above is a yellowish ochraceous-buff, noticeably brighter than 

 that of Mus bentincanus. Underparts whitish cream-buff, the throat 

 crossed by a yellowish ochraceous-buff stripe about 30 mm. in width. 



Measurements. — Measurements of type : head and body, 200 ; tail 

 imperfect; hind foot, 42 (40) ; skull, greatest length, 47; zygomatic 

 breadth, 21. 



Specimens examined. — Seven (two skulls without skins), all from 

 Chance Island. 



Remarks. — As in the other insular forms of the Mus surifer group 

 the tail is shorter than the head and body.^ In all five specimens 



' See Proc. Biol. Soc. Washington, xiii, p. 190, December 21, 1900. 

 ^ In an adult male (No. 104,284), with head and body the same length 

 as in the type, the tail measures 178 mm. 



