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. sylvaticus} 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 Apodemus. 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 w^ and n^ {?\. XXVIII., Fig. 7) is reduced or 

 obsolete ; in m^ and m.^ the outer row of tubercles is reduced to 

 a low, laterally compressed ridge or cingulum. There are 

 eight mammae, of which two pairs are pectoral and two pairs 

 inguinal. 



Scharff {Hist. Eur. Fauna, 1899, 4) thinks that the 

 "distribution indicates that the Harvest Mouse has most Hkely 

 originated in the East, and has spread from there westward in 

 recent geological times." No fossil remains of Micromys 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. 



' See below, p. 565. 



"' We are informed by Oldfield Thomas that on examining reliable material 

 recently he found that Blyth's Mus erythrotis, described from the Khasia Hills, 

 Assam, is a species ai Micromys. 



VOL. II. 2 N 



