?86 joukiJAL, BOMBAY Natural history society, Voi. xiv. 



inflated anteriorly. Palate and rostrum very unlike those of any of the allied 

 species, the differences due to the combined reduction in size of the teeth 

 and elongation of the rostrum. The length of toothrow is contained fully 

 twice in length of diastema, instead of about once and a half, as in Mus 

 vociferans and Mus validus. The incisive foramina share in the elongation 

 of the rostrum to such an extent that they are much longer than the 

 toothrow instead of distinctly shorter. Except that it shares in the 

 general slender form of the skull, the mandible shows no characters of 

 importance. 



Teeth. — The teeth differ from those of 3Jus vociferans in size only, as the 

 enamel pattern of the two species is similar throughout. 



Measurements.— 'External measurements of type : Total length, 442 mm. ; 

 iead and body, 249 ; taU, 193 ; hind foot, 47 ; ear from meatus, 24 ; ear from 

 crown, 20 ; width of ear, 16. Average of ten adults from the type locality: 

 Total length, 437 ; head and body, 241 ; tail, 198 ; hind foot, 48 ; hind foot 

 mthout claws, 46. 



Cranial measurements of largast specimen: Greatest length, 55*4 mm. ; basal 

 length, 50; basilar length, 47; palatal length, 28; least width of palate 

 between anterior molars, 6 ; diastema, 18 ; length of incisive foramen, 10*6 ; 

 combined breadth of incisive foramina, 3*8 ; length of nasals, 22 ; combined 

 breadth of nasals, 5'4 ; zygomatic breadth, 25 ; interorbital breadth, 9 ; 

 breadth of braincase above roots of zygomata, 18 ; mastoid breadth, 19 ; 

 occipital depth at front of basioccipital, 14*6; fronto-palatal depth at 

 posterior extremity of nasals, 13 ; least depth of rostrum immediately behind 

 incisors, 9'8 ; mandible, 31 ; maxillary toothrow (alveoli), 8'2 ; width of 

 front upper molar, 2"4 ; mandibular toothrow (alveoli), 8*4. 



Specimens exa/ftwjec?.— Eighteen, all from the type locality. 

 Remarks. — In general appearance Mus stoicus resembles Mus validus, but 

 the skull is much more slender. It is, however, in no way distantly related 

 to the large rats of the Malay Peninsula. 



Dr. Abbott writes as follows of the rata of Henry Lawrence Island 

 (Mus stoicus and 3fus fiehilis) : — 



Trapped in the dense jungle with which the island is covered. Note that in this lot there 

 are two distinct species : one large with tail shorter than head and body \_M, stolcusl, and one 

 Binaller with tail longer than head and body [If. fiehilis']. The tail is more hairy in the 

 smaller species. Both were caught in the same places, on the west side of the island on 

 Kwantung Straits, at two localities aboat two miles apart. The smaller one squeals pite* 

 onsly when caught in a trap, but the larger is silent. 



Mus TACiTURNus, new species. 

 Type.—Mv\t male (skin and skull). No. 111828, U. S, N. M. Collected on 

 South Andaman Island, Andamans, January 16, 1901, by Dr. W, L, Abbott. 

 Original number, 854. 



Characters. — Slightly larger than Mus stoicus, and colour both above and 

 below more tinged with yellow. 



