MICROMYS 553 
fitting it for a life spent largely in climbing the slender stems of 
grains and grasses. The size is diminutive, and the build 
elegant and slender; the weight of an adult is scarcely more 
than one-sixth of that of an adult A. sylaticus.’ The tail is 
prehensile (a character unique among British mammals). In 
the large hands and feet the pads are of large size and some- 
what modified form; they serve apparently, as in many other 
climbing mammals, the purpose of ‘“‘climbing-irons.” In the 
ear the antitragus is developed as a large triangular valve 
which is capable of completely closing the meatus. The eyes 
are smaller and less prominent than in Afodemus. In the skull 
(as in many climbing mammals) the brain-case is relatively 
large; the facial region, particularly the rostral part, relatively 
small. The cheek-teeth are essentially like those of Apodemus, 
but cusp 5 in m' and m*(Pl. XXVIII. Fig. 7) is reduced or 
obsolete ; in #, and #, the outer row of tubercles is reduced to 
a low, laterally compressed ridge or cingulum. There are 
eight mammez, of which two pairs are pectoral and two pairs 
inguinal. 
Scharff (Ast. Eur. Fauna, 1899, 4) thinks that the 
“distribution indicates that the Harvest Mouse has most likely 
originated in the East, and has spread from there westward in 
recent geological times.” No fossil remains of M/zcromys have 
so far been detected ; but the existence of the species in Japan 
points to its being of ancient standing in the East.” Among 
Oriental mice, the arboreal genus Vandeleuria presents a 
close resemblance to Micromys in skull and teeth; the hinder 
part of the palate is, however, simpler and more normal in 
structure. 
1 See below, p. 565. 
* We are informed by Oldfield Thomas that on examining reliable material 
recently he found that Blyth’s A/us erythrotis, described from the Khasia Hills, 
Assam, is a species of Micromys. 
VOL. II, 2N 
