46 Records of the Indian Museum. [Voi,, III, 



with these are numerous flat, pointed spines of a Hght gre}' 

 colour, with black tips. Besides these there are many slender bristles , 

 about 3 cm. in length and black in colour, showing a dark green 

 iridescent lustre. The green lustre can be seen on a single extracted 

 hair if light comes to it at a particular angle ; it is often to be seen 

 on the bristles of Mus rattus, especially when they are w^et. There 

 is no sign of a yellow or brown tint in any of the hairs. The \entral 

 fur is dark slate-grey. The second specimen, a female measuring 

 144, 201, 33, 24, is at a yard's distance almost indistinguishable 

 from the other ; close examination, however, shows that it differs 

 in the following respects. The light grey spines are much les? 

 numerous, and less conspicuous among the fur. The bristles are 

 not more than 2 cm. in length and do not show iridescence. There 

 is a brownish element in the general colour. The fur of the flanks 

 and shoulders especially shows a distinct trace of 3'ellowish 

 brown. 



It is remarkable that these two black rats, although obviously 

 mature, are the two smallest specimens in the whole collection. 

 There is some evidence to show that the black Mus rattus is usually 

 smaller than the brown, Hossack, in speaking of the few black 

 rats obtained in Calcutta, says, " except that none of the eight 

 exceed i6"5 cm. in length, there is nothing in either the bod}' or 

 cranial measurements to distinguish them from normally coloured 

 rats." We have received four black and three brown specimens of 

 Mus rattus from Freemantle, Australia. The former are all smaller 

 than the latter. 



It has been shown in describing the rats of Rangoon that 

 blackness is not associated with smallness in the allied genus 

 Gunomys. 



The skulls of these two black rats from Cawnpore are some- 

 what unlike one another ; although there is only half a millimetre's 

 dift'erence between their total lengths, there is a difference of 2 mm. 

 between the lengths of their nasal bones. 



Clip. 2 — 



Includes seven specimens in which the fur covering the 

 lower surface of the throat, breast and belly is white. In two 

 of these the ventral fur is long and pure white, perhaps with a 

 faint tinge of lemon-yellow, but there is no coloured stripe in the 

 middle hne of the breast. In the other five there is some colour 

 in this situation ; in one the hairs in the mid-pectoral line are pale 

 grey, in another pale grey tipped with fawn, in a third the coloured 

 line is very distinct and joins a transverse line which crosses the 

 breast between the fore legs. 



Cnp. 3— 



This includes the remaining nineteen, all of which are dark- 

 bellied, each ventral hair being, as usual^ dark grey, tipped with 

 yellowish or reddish brown. 



