36 Records of the Indian Museum. [\"ol. Ill, 



inconspicuous. Some of them have well-developed bristles which 

 are in one case as much as 5 cm. in length. 



The characteristic feature of the race is the bicoloration 

 of the tail. In all the lower surface of the tail is devoid of 

 pigment, and is sharply marked off from the pigmented upper 

 surface. The ears are covered with fine hairs which are longer 

 and more plentiful than those found in lowland rats. This 

 peculiarity is doubtless concomitant with the general plenitude 

 of the fur. It causes the margins of the ears to appear as though 

 fringed with white hairs. Microscopical examination, however, 

 shows that the hairs of the margin do not differ, in the distribution 

 and amount of their contained pigment, from the hairs which cover 

 the whole outer surface of the ear. It was found that all the 

 hairs on the ear are pigmented only in the stouter basal half, — the 

 finer terminal half appears like clear glass beneath the microscope. 

 The actual margin of the ear supports few or no hairs. The ap- 

 pearance of the white fringe received by the naked e^'^e, is due 

 to those hairs which, arising close to the margin, project beyond 

 it. It will be seen that this detail is of importance. This race 

 has been regarded as Mus vicerex. On page 358, vol. xvi of the 

 Bombay N. H. S. Journal, Colonel A. E. Ward states : " We 

 have practically settled that Mus vicerex is the common rat of 

 Kashmir." From the context it appears that this determination 

 was made at the British Museum, where the type of Mus vicerex 

 from Simla reposes. The eight specimens forwarded by Dr. Mitra 

 all agree in being reddish grey above and pure white below, in 

 possessing short bicoloured tails and apparently white-fringed 

 ears. These are the essential characters of Mics vicerex. It is, 

 however, by no means certain that the Kashmiri race is in direct 

 genetic relation with that rat found at Simla which is the type of 

 Mus vicerex, for most of the races of Himalayan rats have short 

 tails, and the white-fringed ear seems merely a concomitant of the 

 general abundance of the fur. The same character is well shown by 

 our specimens of Mus blanfordi (Nilgiri Hills), which species also 

 possesses sleek abundant fur, but is certainly not closely related to 

 Mus vicerex. The question whether bicoloration of the tail can be 

 independently acquired on many occasions will be discussed later 

 on. This particular character was met with in a single rat in 

 Rangoon which appeared to be a sport ; and also, in an unstable 

 condition, among a small community of rats in Naini Tal. If we 

 deny the possibility of its manifold origin we should do the same 

 for the character of albiventralism, regard the white-bellied rats 

 of Tellicherri, Cawnpore, Calcutta and other places as of one stock, 

 and suppose that they hold themselves aloof from the other rats of 

 those places. 



The skulls of these eight rats do not seem to differ from those 

 of the lowland rats. 



The tail of one of the Kashmir rats, though darker above, 

 shows a certain amount of pigment in the skin and hairs of the 

 lower surface. 



