65 



On Rattus blythi Kloss (Mus cinnamomeus Blyth). 



With remarks on allied forms. 



By C. Boden Kloss, f.z.s. 



In a collection of mammals made by Mr. K. G. Gairdner near 

 Raheng, Western Siam, are several examples of a rat which I iden- 

 tify, after comparison with the type, as Rattus blythi mihi (Mus 

 cinnamomeus Blyth) — a form that does not seem to have been met 

 with since it was first described by Blyth in 1859 and given a name 

 unfortunately preoccupied and therefore untenable. 



Mr. Gairdner's series consists of seven skins and six skulls 

 taken during February and March, 1917, at Me Taw and Sikawtur, 

 1500 ft., about 40 miles N. W. of Raheng - a locality a hundred 

 miles distant from' Shwegjnn in North Tenasserim where the type 

 specimens were obtained by Major Berdmore. 



In 1917 I contributed some notes to the " Records of the 

 Indian Museum " (vol. xiii, p. 7) on the tailless type of " Mus cinna- 

 momeus " and comjured it with Rattus cremoriventer cremoriven- 

 ter, l which it closely resembled in colour. 



Mr. Gairdner's specimens show, however, that R. blythi has a 

 bicoloured tail - a character that at once proves it to belong to a 

 different species ; for cremoriventer has a tail dark throughout and 

 also almost pencillate, while that of blythi, though well clad in a 

 normal way, has no elongate hairs at the tip. 



Further, while the upper pelage is of the same composition 

 and of practically similar colour, the fresh specimens show that 

 blythi is beneath of a whiter, less creamy tone than cremoriventer. 



As regards the skulls, those of blythi have less spatulate 

 nasals but broader anteorbital plates, while the palatal foramina 

 extend back to a line joining the front molars : in cremori venter 

 they fall short of this. 



The upper incisors of blythi curve backwards noticeably more 

 than do those of cremoriventer, which in this respect is resembled, 

 among rats of this group directly known to me, only by Rattus 



1. Vide Notes on page 68 postea. 

 VOL. IV, NO. 2, 1920. 



