Descriptions of East Asiatic Mammals 267 
The subgenus Neodon is characteristic of south-central China 
and extends into the highlands of southern Yunnan. Recognized 
species are the typical species, Micro tus sikkimensis, M. irene 
from Yunnan, Szechwan, and Kansu, and M. forresti from 
southern Yunnan. The Mice of this subgenus are separated 
from Micro tus on technical grounds. They are not fossorial; 
they have the mammary formula of Micro tus (8 nipples) but 
the tooth structure of the Pine Mice. 
The subgenus Stenocranius is northern. It occurs from Mon- 
golia to Siberia eastward and westward to Europe. Microtus 
slowzowi is typical. Eastern forms are Microtus brandti aga and 
M. michnoi, both from the Transbaikal region ; M. koreni from 
the Kolyma River region, northwest of the Sea of Okhotsk; 
M. gregalis, with its several races, from eastern Siberia; and 
M. tshuktshorum from Plover Bay, extreme eastern Siberia. 
The species of this subgenus are distinguished by having nar- 
rower skulls than those of true Microtus. 
The Meadow Mice included in the subgenus Microtus in the 
most restricted sense are probably best known to residents of the 
eastern United States through M. pennsylvcmicus, common in 
all our waste fields and pastures. These Mice are gray-brown in 
color and have short tails. They may sometimes be seen running 
along their runways in late afternoon. The typical species is the 
European M. terrestris (= arvalis Pallas). 
In the Far East of Asia the pattern of distribution of true 
Microtus is singularly like that of the shrew-genus Sorex, 
namely, a great concentration of forms in the north, a minor 
aggregation in the highland of southwest China and in Tibet, 
and few species in the intervening lowlands of east China. In 
northern Burma and Tonkin the microtines are represented 
chiefly by Eothenomys. Beginning in the northeast, there is M . 
camtschaticus from Kamchatka and M. uchidce from Para- 
mushiro, one of the northern Kurile Islands; M. koreni from 
the Kolyma River northwest to the Sea of Okhotsk; M. oecono- 
