rgog.] R. E. I^i^oyd : The Races of Indian Rats. 23 



the human disease lencoderma ; it was, however, felt to be impossible 

 to explain these extraordinary' rats as pathological freaks, for the 

 two resemble one another not onh' in their tails but also in the 

 forehead star, in size, and in the light brown colour of the coat. 



Seven species of rats have been recorded from Celebes and the 

 Philippines, in all of which the distal third of the tail is devoid of 

 pigment. They have received the names Mus xanthurus, cele- 

 bensis, meyeri, cverctti, macleari, hizonicus ; together the}' form the 

 '' Xanthurus group " [8]. There seems, therefore, little doubt that 

 rats showing this peculiarit}^ are an established race in that part 

 of the world. The}' must be as variable as the rats of India, for 

 when m.et with they have, more often than not, received a differ- 

 ent specific name. If the figure of the tail shown on plate i be 

 compared with the illustration of the tail of Mus macleari shown 

 on plate xii, P.Z.S., 1887, no difference can be seen in the appear- 

 ance of the two appendages. One cannot escape from the con- 

 clusion that the character, terminal caudal albinism, w^hich is evi- 

 dently the mark of a successful race in the neighbourhood of the 

 Philippines, has arisen in the Punjab quite independently on this 

 occasion and probably on mam^ other occasions, in many other 

 places. These sports can not be explained as reversions. Even 

 if one makes the absurd supposition that the Xanthurus group 

 represents the parent stock of the Punjab rats, the latter race must 

 be separated from the former b}' a vast number of generations, 

 for nearly two generations of rats pass in one 3^ear. 



Pjb. 4, a Mus rattus with a white-tipped and tufted tail — 



The last centimetre of the tail of this rat and the hair upon it 

 are white. The white hair is usually long and projects 6 mm. be- 

 yond the fleshy tip. This case is perhaps of small importance ; 

 similar sports were noticed among the rats of Calcutta ; the}- are 

 especially common among Mus concolor. The same character has 

 been noticed in Gujtomys and Bandicota. This case is mentioned 

 because of the concomitant lengthening of the hair. As the case 

 of Pjb. 3 recalls the Xanthurus group of the Philippines, so in a 

 lesser degree does this case recall Mus hlanfordi of the Nilgiri Hills 

 (Madras), the principal feature of which is a tail white in its distal 

 half with lengthening of the terminal hairs. 



Pjb. 5, Gunomys sp. — 



No less than 157 rats of this species have been sent by Davj-s 

 from fields in the Amritsar district. They resemble one another in 

 having a tail proportion of about 75 %, a hind foot proportion of 

 about 17 %. Their skulls are short and broad, and can be recognised 

 at a glance from those of all other rats. Their skulls, however, 

 resemble those of the newly defined genus Nesokia, except that in 

 that genus the incisor teeth are broader and the palatine fora- 

 men is concomitantly much shorter than in Gunomys (plate iii). 

 The female Gunomys has a continuous row of teats on either side, 



