igo;.] 



Dr. Hossack : The Rats of Calcutta. 



17 



frequently sullied, sometimes brown or grey and occasionally with a white, fulvous 

 or grey median band. Tail uniformly brown throughout. 



" In Bombay at least one-third of the rats are typical Mi4S rattus, i.e., black, but 

 in other parts of India this does not appear to be the case. 



" It must be remembered, however, that this rat is o'ften far from being black, 

 varying from brown to almost white. "^ 



The colour usually found in Calcutta is a rather light-brown with a clearly defined 

 yellow- white belly, white tinged with lemon yellow extending to the throat and the 

 inside of the limbs. A very pretty variation is sometimes seen in which the white 

 of the belly is separated from the upper brown parts by a narrow line of burnt 

 sienna. The brown of the upper parts varies from a dull vandyke brown to 

 a distinctly rufescent or sienna- tinted brown. Again, rarely, the brown may be so 

 pale as to become almost a yellow, i.e., a faint cinnamon brown. The middle line of 

 the back, as in most rats, is much darker than the rest. Whereas in about 50 per cent, 

 of individuals the yellow- white belly is found, in the remainder the belly is grey or 

 orange-grey, a curious tawny mixture, produced by orange or ochraceous tips mixed with 

 grey. Between the white and the grey or orange-grey belly every possible combination 

 is found, from a white belly with a single spot or streak of grey under the throat to one 

 where the streak has spread out into a great breastplate of grey that leaves only a margin 



of white. Where the whole belly is grey, 

 the only trace of intrusive white may be 

 a white spot or star under the throat or 

 small circular patches round the nipples. 

 As showing how endless are the combina- 

 tions and variations of these different belly 

 colourings, the figure in the text may be 

 referred to, showing the different variations 

 found in nine specimens of M rattus, which 

 represented the total bag for one day. 

 Only two out of the nine rats showed the 

 same pattern, one being a very large adult, 

 the other a small one. The skin with the 

 grey breast stripe did not occur in this parti- 

 cular batch, but it is included in the draw- 

 ing as being a common type of coloura- 

 tion. Where the fur of the belly is white 

 the skin is also white instead of being 

 bluish-grey as it normally is on belly, 

 back and sides. If the fur of the belly is 

 grey the skin is also foimd to be grey. 

 Black Form. — A comparison of the 

 black form with skins from Oxford in the 



1 Plague, Rats, and Fleas, Liston, Captain, I.M.S., Journ. Bombay. Nat. Hist. Soc, vol. xvi, p. 253. 

 8 



