28 ARKIV FÖR ZOOLOGI. BAND 10. N:0 20. 



8. Sciiirus tennis Horsf. — 1 ^ ^Vi 1915. Nose to vent 

 = 128; Tail = 108; Hindfoot == 34 mm. 



Skull measurements: Great est length = 36,3; length from 

 condylus to gnatbion = 31,? ; basicranial length = 27, o ; greatest 

 breadtli of brain case==17,o; zygomatic width = 20,o; least 

 interorbital widtli = 10,8 ; least postorbital width = 13,3; 

 length of nasals mesially = ll,o; breadth of combined nasals 

 at anterior extremity = 4,5; breadth of combined nasals at 

 posterior extremity = 2,5; diastema == 8,0; length of upper 

 toothrow = 6,3 mm. 



The above-mentioned specimen belongs to the typical 

 form and not to the race described by Miller under the 

 name of T. tenuis surdus (Proc. Wash. Acad. Sci., 1900, p. 8). 

 In this latter race the general colouration is duller and there 

 is no trace of the ochraceous colour of the flanks atid should- 

 ers which is conspicuous in the typical form. 



9. Rattiis asper Miller. — 1 J 171 1915. Nose to vent 

 = 128; Tail -^ 105; Hindfoot = 27 mm. 



The single specimen obtained agrees perfectly Avell with 

 the type specimens from the mountains of Träng in Lower 

 Siam as described by Miller (Proccedings Biol. Soc. Washing- 

 ton, Vol. 13, p. 145, 1900). The underparts of the body are, 

 however, not dull buff but almost grey, which colour is 

 sharply defined from the colour of the sides. The fur is^ 

 everywhere dusky at base. In my specimen there is no trace 

 of a tawny spöt on the chest. In the original description 

 Miller writes that B. asper seems to be closely related to 

 the Bornean Rattus lohiteheadi Thos. a species which, how- 

 ever. Miller then only knew by description. In its general 

 aspect it certainly shows a resemblance to the Bornean 

 species, but it may at a glance always be distinguished from 

 that form already by its colour, which in Rattus tchiteheadi 

 is much more tawny on the upper parts of the body. In 

 the two specimens of R. ivhiteheadi with which I have com- 

 pared it, the bellies are almost ochraceous. In the Bornean 

 form the tails also seem to be shorter, though of the same 

 colouration. Some cranial differences are also visible. The 

 most visible is the general aspect of the foramina incisiva 

 which in Rattus asper are fairly long and narrow, thus more 

 resembling those of the Rattus surifer-GROJJT. The whole 



