30 Memoirs of the Indian Museum. [Voi<. I, 



Mus (Nesokia) bengalensis , Thomas, P. Z. S., 1881, p. 526 ; Anderson, Fauna 

 Mergui Archip., i, p. 341. 



Yenkrai, Beng. ; Kok, Can. ; Golatta koku, Tel. of Yanadis ; Rekywek, Bur- 

 mese. 



This is the commonest rat in Calcutta and probably the one most concerned in the 

 dissemination of plague, being the predominant species in grain godowns, which have, 

 in Calcutta and elsewhere, notoriously been the centres from which plague has spread. 

 Major lyconard Rogers, I. M.S., has kindly examined for me sick specimens and has found 

 them suffering from plague.' Its general characters will be found described in the key. 

 It has apparently been much confused withM. decumanus in the past, but the character 

 of the footpads, the relatively small foot, the tail, bristles, and colour of the feet and 

 muzzle, will always distinguish it, while the broad, short, arvicoline head is also charac- 

 teristic. The fur is coarse and thin, so that when the rat bristles when enraged, the 

 naked skin can often be seen ; when drowned the animal frequently looks half naked, 

 with the large teats in the female very prominent. The fur is composed of three ele- 

 ments, as follows : {a) Underfur pale, grey, coarse, scanty, found all over except on the 

 upper surface of the feet and the anterior lower surface of the throat. (&) Coarse, pointed 

 hairs, 1-25-1 -5 cm. long, most of which are black below with straw coloured or cream buff 

 tips, sometimes surmounted by an extreme tip of black. Mixed with these, are similar 

 hairs rather longer and coarser, black throughout ; both these kinds of hair may have 

 pale grey or isabelline bases. Towards the underparts the yellow tips get paler till on 

 the belly and throat dirty white or white hairs are found mixed with the black, (c) 

 lyong, black piles, 4-5 cm. long. These are very characteristic ; they are found all 

 down the back and partly down the sides, but are most marked on the rump. 



Whiskers. — These are black, mostly tipped with pale sienna or ochraceous buff. 



Colour. — The general colouring is very similar to that of M. decumanus, but the effect 

 is a colder, greyer brown. Down the middle line of the back, the mixture of black tips 

 with ochraceous buff gives a fairly rich brown, but as the sienna tips grow paler down 

 the sides, a greyish grizzled-brown results, getting dirty greyish- white on the underparts. 

 Just under the throat and on the inside upper surface of both feet, and the inside of the 

 legs, dirty white is found ; but not enough to affect the general undercolour, which is 

 grizzled greyish. The muzzle is a rather livid flesh colour, as are also the feet, markedly 

 darker than the flesh colour of M. decumanus, the feet being faintly atreous. Anderson 

 makes the feet and muzzle in A^^. blythianus flesh coloured, but in N. providens dark 

 flesh coloured. N. providens is, according to him, a Southern Indian or Ceylon rat, 

 while N. blythianus is common in Calcutta. As a pure field rat the former tends to be 

 lighter in colour and occasionally rufous. 



Tail. — The tail is rather characteristic in shape ; it is very thick at the base and 

 tapers suddenly, so that the extremity looks attenuated compared with the heavy 

 uniformly tapering tail of M. decumanus. It is irregularly, but very distinctly, 

 annulated, the rings averaging in the centre about 12 to the cm. The scales are 



Calcutta Plague Report, 1905-06, p. ii, Appendix A. 



