484 PROCEEniNGS OF THE NATIONAL MUSEUM. vol. xxxvi. 



MUS LINGENSIS Miller. 



1900. 3Ius lingensis Miller, Proc. Washington Acad. Sci., II. p. 206, Aug. 

 20, 1900. 



Of this rat, which is so widely distributed in the Rhio-Linga 

 Archipelago, Doctor Abbott secured 10 individuals (8 skins and 

 skulls, and 2 in alcohol) on Pulo Jombol. 



For external and cranial measurements, see table, page 485. 



MUS FIRMUS Miller. 



1902. Mils firiniis Miller, Proc. Acad. Nat. Sci., Philadelphia, 1902, p. 155, 

 June 11, 1902. 

 Two specimens from Pulo Setoko do not differ from 3Ius firmus 

 as found elsewhere in the Ehio-Linga Archipelago. 

 For measurements, see table, page 485. 



MUS CHOMBOLIS, new species. 



Type.— Skin and skull of adult female, Cat. No. 144393, U.S.N.M., 

 collected on Pulo Jombol, Rhio-Linga Archipelago, March 10, 1907, 

 by Dr. W. L. Abbott. Original number, 5100.- 



Diagnostic chardctcrs. — Simihir to Miis frnif/s Miller,° but slightly 

 darker in color, smaller in size, and with distinctly smaller skull. 



Color. — Upper parts and sides of head and body, a coarse grizzle 

 of brownish black and pale ochraceous buff, the brownish black in 

 excess along the dorsal line. Along the sides the slate gray of the 

 imderfur shows through on the surface. IJnderparts and inner sur- 

 faces .of legs dirty cream color; feet dull brownish, tail and ears dull 

 dark brownish. 



Pelage, etc. — The pelage consists of three types of hair — the rela- 

 tively short, dark, gray underfur; soft, weak hairs, with dark-gray 

 bases, light ochraceous buff subtarminal rings, and short blackish- 

 brown apices; relativel}^ long^ -soft, grooved, brownish-black bristles. 

 Tail concolor, dark brownish, 10 scales to the centimeter in the middle 

 portion; each scale subtended by 3 hairs, each of which is equal to 

 about 1 scale in length. 



Skull and teeth. — The skull of HI us chomholls in general resembles 

 that of M. fn)u(s, but is distinctly smaller and lighter throughout, 

 especially noticeable in the rostral portion, which is much shorter 

 and narrower and much less deep; the bulla? are smaller; the incisive 

 foramina shorter; the anterior nares smaller. The maxillary tooth 

 row is distinctly shorter in M. chombolis than it is in M. fi.rmus and 

 the individual teeth smaller ; the incisors are also smaller and w^eaker. 



" Proc. Acad. Nat. Sci. Phila., 1902, p. 155, June 11, 1902; Proc. U.S. Nat. Mus., 

 XXXI, No. 1485, p. 2GG, Sept. 11, 190G. 



