70 RATS AND MICE. 



arched skull. It approaches more nearly to M. calainorum the 

 Yang-tze reed-vole. The other, M. oniscus, was a discovery of Dr. 

 J. A. C. Smith, and is a very small member of the genus. 



In South Shensi occurs a subspecies of M. caJamomim. It was 

 recently described as new under the name, M. c. superbus. It is very 

 much larger than any of the species hitherto mentioned. 



There are two subgenera of the genus Microtus, namely Microtus 

 (Caryomys) and Microtus {Ethenom.ys). The first of these is repre- 

 sented by three species, namely Microtus (Caryomys) inez from West 

 Shensi, M. [0.) mix from Southi Shensi and M. (C.) eva from West 

 Kansu, — all of which were discovered by Anderson. These are small 

 rich coloured voles. Microtmis (Eothcnomys) mclanognster is the only 

 member of the second subgenus so far discovered m China. It is 

 found in Western Kansu as well as in Sze-chuan. 



A third genus, Procdromys, has also recently been described 

 from Western Kansu. So far it contains only one species, Proedromys 

 bedfordi. This species is mainly characterized by iis excessively 

 long hair. Otherwise, in general appearance it resembles M. malcohni. 

 I have recently secured some interesting voles from jNIanchuria but 

 these are as yet unidentified. There are also many species in other 

 parts of China, notably in Sze-chuan province, which, however, do 

 not concern us in this paper. As far as my experience goes, none of 

 these voles make good pets, being excessively shy and inclined to 

 bite, when their sharp and powerful teeth inflict nasty wounds. 

 Many of them seem to be partially diurnal in their habits, though 

 one or two are purelj' nocturnal. 



The next group we have to consider is that of the true rats and 

 mice. Under this heading we have twelve species and subspecies, 

 contained in the four genera, Mus, Epymis, Apodcnrus and Micromys. 



In the first of these comes the common rat (Mas rattus), the 

 common mouse (Mus 'tragncri) and its sub-species Mus wagneri 

 viongoliiim, none of which need any description, except to say that 

 the subspecies M. v. mongolium is slightly darker than i\/. ivagncri 

 In Manchuria I have found an even darker coloured form. Mus 

 gansuensis is another closely related form, found in Western Kansu. 



The genus Epymis includes what have been called the rock cr 

 sulphur-bellied rats. These are comparatively large animals not un- 

 like the common rat, but of a more delicate build, with longer ears 

 and longer, more hairy tails. There is a tendency to spinyuess m 

 the hair of the back, and three, at least, of the four forms have 

 pale sulphur-yellow beUy fur. 



