564 MURIDA—MICROMYS 
bulla, 31-5 to 34-4; (9) and (10) nasal length and breadth, 29-2 to 
36 and 8-6 to 11-5; (11) palatal length, 50-9 to 54:3 ; (12) diastemata, 
22-1 to 25-2; (13) incisive foramina, length, 17-6 to 20-6. The 
dimensions not mentioned here are in substantial agreement with 
those of the Field Mice. 
The mandible is much like that of the Field Mouse in form, 
differing, apart from its much smaller size, only in some slight details 
of the angular and coronoid processes, the former being a little more 
concave above, the latter a little more recurved. The cheek-teeth 
(Pl. XXVIII, Fig. 7) are described above under the genus. 
Geographical variation:—In addition to 4/7. m. soricinus and 
minutus (of which last no specimens have been seen), five or six other 
sub-species are at present recognised. Of these, JZ. m. pratensis, 
Ockshay (Mov. Act. Phys.-Med. Acad. Caes. Leop. Car. Nat. Cur., xv, 2, 
1831, 243, described from Western Hungary), ranges throughout 
Hungary into Rumania. In this form, as described by Miller, the 
posterior half of the body and the outer surfaces of the hind legs are 
as in sorzc¢nus, the head and the anterior half of the body are decidedly 
greyish, the white under parts receive a bluish tinge from the slaty 
hair-bases, and the tail is rather sharply bicoloured. In a series 
collected at Csehtelek, Eastern Hungary, during October and November 
1913, by Fraulein von Wertheimstein, specimens with unworn or very 
slightly worn teeth (condylo-basal length from 15-6 to 16-5 mm.) have the 
coloration as in prazenszs, the rufous tint so characteristic of similarly 
grown British Harvest Mice only appearing towards the rump; in a 
female with slightly worn teeth (head and body, 63; condylo-basal 
length, 16-9 mm.) the colour, save for slightly darker flanks, is nearly 
as bright and rufous as in specimens taken at Colchester in April; in 
a fully adult female with half-worn teeth (head and body, 71; condylo- 
basal length, 17-8 mm., B.M. No. 14.1.3.35) the colour is quite as 
red and bright on the head, back, and flanks as in the brightest 
English specimens; the hairs of the belly and chest are pure white 
to their bases, and on each side between the white belly and the 
rufous flanks there is a narrow belt of almost pure buff. 
The remaining sub-species are Asiatic. 17. m. batarovi, Kastchenko 
(Aun. Mus. Zool. Acad. Imp. Sci., St Petersburg, xv., 1910, 284), from 
the Transbaikal, is characterised by its short tail, measuring only from 
60 to 70 per cent. of the length of the head and body ; by its dark back, 
rufous towards the rump, and its ashy-white belly. d/us minutus, var. 
kytmanovt, Kastchenko (0p. céz.), is described as an intermediate 
between typical mznzutus and éatarovt. M. m. ussuricus, Barrett- 
Hamilton (Aun. and Mag. Nat. Hist., April 1899, 344), described from 
Ussuri, Eastern Siberia, is a dark-backed form with the belly washed 
with dirty yellow, and no distinct line of demarcation. J/. m. pygmaeus, 
a 
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