RATS AND PLAGUE, 163 
(1) Mus decumanus, Pallas. The Brown or Norway Rat. 
(2) Mus grisewenter, Bonhote. The Malay House or 
Roof Rat. : 
(3) .Mus concolor, Blyth. The Little Rat. 
(4) Ofless importance are Gunomys varius, Thomas. The 
Eastern Bandicoot-rat. 
(5) Gunomys varillus, Thomas. The Little Bandicoot-rat. 
Mus musculus, Linn. The Common Mouse, is probably 
harmless; it is in any event so rare as to be negligible and the 
latter may also be said, with regard to their occurrence in 
towns, of Mus jalorensis Bonhote, a whitish- bellied member of 
the rattus group. 
Though one or two Indian squirrels are regarded with 
suspicion, Malayan squirrels—owing to their different habits— 
need not be taken into account at all. 
The species of bandicoot-rats listed above have recently 
been described from Penang specimens: Gunomys varius differs 
but slightly from G. bengalensis Gray, the well-known Indian 
species and G. varillus, as its name indicates, is a small form of 
G. varius. The latter has lately been taken in large numbers in 
Rangoon and has probably been carried thence to Penang in 
rice-ships. The bandicoot-rats are certainly introduced species 
in the Peninsula, they seem to have -been recorded hitherto 
only from Penang but lam awareoftheir occurrence in Singapore 
though I have never examined specimens. Cantor in 1846 
(J. A. S. B. vol. XV), recorded Mus bandicota, Bechstein, 
(= Bandicota nemorivaga, Hodgs.) from Penang and the Pen- 
insula and this species possibly occurs in Singapore also. 
Though the bandicoot-rats are known vehicles of plague 
hosts, it is probable that they exist in such small numbers 
locally as to be of minor importance. 
Mus decumanus is a ship rat which scarcely occurs out- 
side large ports (Singapore, Penang, Malacca and Port Swetten- 
ham) though I have taken a few individuals in Johore Bahru. It 
is one of the most dangerous species owing to the large number 
of parasites it harbours. And here it may be pointed out that 
just as the Anopheles mosquito is the conveyer of malaria, and the 
R. A. Soc., No. 57, I9I0. 
