igoy.] Dr. Hossack: The Rats of Calcutta. 31 



square with rounded corners ; black pointed hairs about one and a half to two rings 

 deep are set under the scales. Under the base of the tail these are longer, and occa- 

 sionally a few of them are white. The scales generally overlap, but sometimes the 

 rings are separated by a dark, flesh coloured interval, giving the tail a brown ap- 

 pearance rather than black. Twice I have come across a white tip to the tail, both 

 scales and hair being white ; this tip extended only 05 cm.' 



Feet. — The feet are dark flesh coloured, or faintly atreous, and with their small, 

 round pads are quite characteristic. The fore foot has the usual five pads, and the 

 hind the usual six, but the proximo-external is so very small that it is easily over- 

 looked. So small is it that it is occasionally absent altogether or it may be absent on 

 one side and only faintly present on the other. The following is the result of an 

 examination of a series of 160 individuals on this point : — 



Normal. Almost absent. Absent one side. Absent both sides. Rather large. 



147 3 2 3 5 



In the five noted as having rather large pads, there was a tendency for the pads to 

 be cordiform as in M. decumanus. The manus shows a rudimentary poUex with a 

 nail, while all the other digits are armed with sharp, white, strong claws. The short 

 hairs covering the feet are dark, except on the inside where they are white ; a 

 few long, white hairs project over the claws. 



MammcB.—The mammae are numerous, large, and easily counted ; generally 14, 

 4 pectoral and 3 inguinal pairs. When large the series is continuous and cannot be 

 properly broken up into pectoral and inguinal. The following is the result of 16 

 observations recorded : — . . 



Rt. U. 



4. 1 ± A * 1 



3 4 4 4 4 4 



5 times 4 times 3 times 3 times ^^ v ^ 



once 



Ears. — The ears are brownish flesh coloured, practically naked, and quite naked 

 on the lower half of the dorsal surface. Their relation to the eye as in all the other 

 Calcutta rats examined, is very variable. Though the ear is short, the head is so short 

 and blunt that in 46 per cent, it reaches or covers the eye. Fifty individuals were 

 examined as regards this point, with the following results : — 



Covers. Half covers. Reaches. Short. Unspecified. Total. 



9 7 12 14 8 50 



Habits. — This rat was originally a burrowing, grainstoring field rat, but in Calcutta 

 it has become markedly parasitic on man, infesting stables and grain godowns. 

 It honeycombs solid brick walls, and I have seen it at midday waiting in its 

 hole three feet up the wall for the horse's stall to be replenished. Recently in 

 our own stables I have found a pile of rubbish 6 ft. x 4 ft. x 9 in. thrown out 



' Since this went to press I have obtained two black-e^'ed albinoes identical in colouring with the 

 albino M. rattus which is figured. 



