26 Memoirs of the Indian Museum. [Vol. I 



Colour. — The general effect is a brown rat a little darker over the middle line of 

 the back, with the colour getting lighter towards the lower part owing to the predomi- 

 nant tips being pale yellow or dirty white. The shade of brown varies considerably, 

 from a moderately rich brown to a rather pale yellowish-brown. There is sometimes 

 a rufous ^ effect from sienna-coloured tips, but this is never marked. 



The undersurface varies considerably, but it is generally a dirty greyish- white, 

 fading gradually into the lighter tones of the lower parts of the side. It may be 

 hoary-grey aU over or whitey-brown, and at times may be an almost clear yellowish- 

 white rather sharply defined, extending over the throat and inner sides of limbs. 

 The occasional sport of a white-tipped tail, noted in Nesokia hengalensis and Mus 

 rattus, has not been observed in this species. 



The whiskers are black, but the hairs lowest on the muzzle are white throughout. 



Tail. — Blanford makes the tail brown all over, and in consequence I was at 

 first very puzzled as to what this decumanus-like rat with a distinctly bi-coloured 

 tail could be. However, I find in the Indian Museum series that five specimens show 

 the bi-coloured tail distinctly, viz., skins Nos. j.f.l. and p. collected in Calcutta by Q.N. 

 Fraser and one (A) collected in Bushire, Persia, by Blanford. Two skins from Gilgit 

 show it slightly, while in three specimens from Saingooting, Assam, and three from the 

 Andamans, the tail is uniformly brown. The fact that the lighter colour of the lower 

 surface may occasionally be so slightly marked as to be easily overlooked, explains the 

 error of previous observers. Out of one particular series of 43 very carefully examined 

 as to the coloration of the tail, three showed a tail at first sight brown aU over with 

 short, black hairs ; but on careful examination it was seen that the tail was dis- 

 tinctly lighter below, the hairs being light brown there instead of black ; in 10 

 the lower surface was markedly lighter due to a mixture of light-brown and 

 white hairs ; in 30 distinctly white below, with white hairs and most commonly 

 white scales. The last two figures are rather arbitrary as every gradation of 

 shade was found, obtained in every possible way, according to the predominance 

 of the scales or hairs in the lightening. Typically, the scales are brown above and horny 

 white below, the rings averaging 6 to 8 to the centimetre, with a limit of 10 to the centi- 

 metre. But the lower scales may be found in every shade up to the darkest brown, in 

 which case the hairs will be white. The hairs, on the other hand, may be black, but 

 the scales will then be white. In one instance the scales were white both above and 

 below, the hairs were black above and below, but the lightening of the lower surface 

 was secured by the black hairs being white-tipped below. But no matter what the 

 shade, white, brown or atreous, it will generally be found that scales and hairs vary in- 

 versely in depth of colour, and the tail is always distinctly bi-coloured. It is very 

 common to find the scales patchy, little islands of horny white scales occurring in 

 the middle of the brown or vice versa. 



' "Rufous" is used as a convenient and generally understood term, signifying reddish, foxy red. 

 Strictly speaking it is an incorrect term, as according to Ridgway it is obtained by the use of the pigment 

 " light red, " a colour never seen in a rat. 



