RATS AND PLAGUE. 159 
genera. These are recognised, at least by Captain Lloyd, but 
throughout the reports we find a blind belief in the pronounce- 
ments of Mr. Thomas as a repudiation of the findings of all other 
systematic workers. Dr. Hossack has omitted to place in his 
list of Indian rats the names of Mus mettadaand Mus humei : 
as the one is included by Mr. Thomas in the paper noted above 
and the other is described by him, it is curious that this author 
does not find them acceptable! 
The bulk of Dr. Hossack’s work which is, as far as it goes 
excellent, is taken up with an account of those rats of Calcutta 
which he has found to be connected with plague; these are 
Mus decumanus, Pallas, Nesokia (Gunomys), bengalensis, Gray 
and Hardw., various forms of Mus rattus Linn., and Nesokia 
(Bandicota) nemorivaga, Hodgs. 
Amongst the animals brought to him the last was very rare 
and Mus rattws only formed about 15 per cent of the total. 
In connection with the others an interesting fact was noted: 
that while in the northern native area of Calcutta, where grain 
stores and huts abound, N. bengalensis and M. decumanus 
occurred or rather were caught, in the ratios of 60 and 26 per 
cent of the total; yet in the central European portion of the 
city these proportions were strikingly reversed, AZ. decumanus 
forming 51 per cent and N. bengalensis only 37 per cent of the 
catch. 
Careful dates for distinguishing the immature from the 
adult animal are given; a key is furnished for distinguishing 
the various species together with elaborate descriptions and 
measurements of each and a supplement contains coloured 
illustrations of the plague rats together with figures of skulls, 
teeth and feet. 
Surgeon-Captain Lloyd’s paper bears the unfortunately 
ambitious title of “The Races of Indian Rats,” though it is 
quickly obvious that the author has an acquaintance with but 
a small section of them. While no doubt where those connect- 
ed with plague are concerned, he is on safe ground, such is not 
the case when he deals with the genus Mus as a whole and 
the confusion then brought about seems to be almost entirely 
R. A. Soc., No. 57, I910. 
