52 
('. Sasaki. 
rather blunt; eyes dark greyish brown ; the upper incisors not projecting 
beyond the snout. liars nearly quadrangular (length 13 mm. brcadtli 8 
mm.), about '/^ as long as the head, with a few hairs on the inner side, and 
their outer side as well as the free edges are covered with greyish hairs. 
They are not completely concealed within the hairs of the head. Incisors 
yellowish brown on the outer side (Figs, i ; i, a. ]'l. IX. 1. Hip glands 
are large and oval. Plantar tubercles 5 (Figs. 3; 3, a. I'l. IX. 1. Mammte 
8, inguinal 2 — 2 ; pectoral 2 — 2. 
Skull long, smooth and flattened ; auditory bulla comparatively large, 
bulky, and oval in shape (Fig. 2. PI. IX. \ Incisive foramina is very small but 
distinct. Of the upper jaw, ist. molar with 4 closed triangles and an anterior 
loop ; 2nd. with three closed triangles, and a posterior triangle with an 
open base ; 3rd. with 3 closed triangles with an anterior and a posterior 
loop, with 4 inner and 3 outer salient angles ; of the lower jaw, ist. molar 
with 5 closed triangles, an anterior trefoil and a posterior loop ; 2nd. with 
four triangles ami a posterior looj), each triangle on the one side confluent 
with that on the other ; 3rd. with 3 long inner and 3 short outer salient 
angles (F^igs. 4; 4, a. PI. IX.). 
In general asjjccts and characters, the present species resembles to a 
certain degree Arvicola subterraneous, Selys., which is described by Mrs. I I. 
Leunis' and J. R. Bos.-; but it differs in the coloration of the fur, length of 
the body and tail as well as the size of the ear. This leads us to give it a 
new name Arvicola hatanedzumi.'' 
Habits : The field mice are mostly found during winter in the farms of 
wheat, tea, mulberry trees and other plantations. In the day time, they 
conceal themselves within the subterranean nests, while at night they come 
out from their hiding places and search for food. If wc feed the mice in an 
enclosure, they remain quiet during the day, but as night approaches they 
become very active and emit a peculiar cry. 
The nest of the mice are usually constructed on the dikes separating 
rice field or mounds, elevated farms scattered over the same field or along 
1 II. Leunis, Synopsis der Thicrkunde Band I. 
- K. Bos, Tierische Schadlinge u. Niitzlingc. 
Hatanedzumi (Jap.) means Farm mouse. 
