36 Memoirs of the Indian Museum. [Voiv. I, 



In general appearance the rat is like a Bandicoot, but the foot is very small and 

 the head is short, bluff and arvicoline, the typical head of Nesokia bengalensis. The 

 pads are small and circular ; the ears are round and relatively short. The eye is very 

 small, -6 cm. long and only "4 cm. wide. As regards colour the throat and cheeks are 

 yellowish- white, while the belly is yellowish-grey, not sharply marked off from the sides 

 and bears an ill-marked grey central stripe. The nose is flesh coloured ; the ears are 

 pinkish-brown and nearly naked. The back is more rufous than usual, as ochraceous 

 buff or pale tawny tips are numerous, particularly about the head and ears. The limbs 

 are grizzled brown outside, white inside. The underfur is very scanty indeed -5 cm. — 

 •7 cm. long, pale grey or isabelline in colour. On the belly are short, stiff hairs 

 I cm. — 17 cm. in length, with grey or isabelline bases and pale tawny or ochraceous 

 tips, sometimes surmounted by an ultimate tip of black. Other hairs are brown or 

 black throughout, or black with a tawny tip. The long black piles of the back are 

 5 cm.— 55 cm. in length. The tail is short and thick and tapers suddenly to a point; 

 the rings in the centre average 10 — 11 per cm., the hairs above are i^ rings deep and 

 black in colour. The scales are greyish-brown. The hairs below are brown, not black, 

 but the lightening of the lower surface is almost imperceptible. The scrotum is of 

 medium size relatively. The skull is rather elongated, 25 per cent, above the average 

 but otherwise is more or less Nesokian in character. It is possible that the diminu- 

 tion of cranial breadth may be due simply to the excessive age of the skull. ^ 



This is not the only reference I have found as to the possibilities of cross breed- 

 ing, for Mr. S. J. A. Salter, in a rather loose description of the " snake rat," in which he 

 identifies it with Mus alexandrinus , describes the interbreeding of Mus alexandrinus 

 and Mus decumanus. The passage is as follows : — 



'' Undoubtedly characteristic specimens of M. rattus, decumanus and alex- 

 ' andrinus may be obtained, but there are intermediate forms in endless variety as 

 ' may be seen by looking at the cages of a rat-catcher after visiting docks. This 

 ' suggests interbreeding. 



'' Some specimens of M. alexandrinus , which had been sent from Alexandria, got 

 ' loose in the gardens (Zoological) some years since, and for a long time afterwards 

 ' the keepers frequently caught cross bred rats, at first half breds, and afterwards with 

 ' less and less of the character of the snake rat, till at length all traces of it dis- 

 ' appeared. In the language of horse trainers the new strain was ' bred out.' The 

 ' capacity for interbreeding appears to be endless and indefinite. Newman has 

 ' suggested that these cosmopolitan rodents are, in their differences, not so many 

 ' species, but mere geographical races. If interbreeding and a resultant fertile off- 

 ' spring determine the specific identity of varying individuals, there is an end of the 

 ' question. The different rats do breed and their progeny are fruitful for any length 

 ' of time and any number of generations."^ 



1 For measurements of the skull see table at the end. 



2 Journ. Linn. Soc, vi, Zool. (1862), p. 71. 



