ALLEN: MAMMALIA. 221 
referred to Radde’s ‘‘Mus sylvaticus var. major” (Reis. Sib., 1862, 1, p. 180). 
In his review of this group, Barrett-Hamilton (1900, p. 412) states that he has 
seen no specimens but considers it as probably “‘the western Siberian representa- 
tive of M. s. princeps”’ of southeastern Europe. He also believes that the speci- 
mens obtained by Przewalski in the mountains of Kansu, and described by 
Buechner as Mus chevrieri, are the same animal. In the absence of material for 
direct comparison, our series agrees well enough with the description to make 
this conclusion seem probable. Sixteen skins with skulls were collected by Mr. 
Zappey at Lianghokow, 12,000 feet; Tachiao, 12,000 to 13,000 feet; Shuowlow, 
13,000 to 15,000 feet; and Ramala Pass, 15,000 feet. Possibly these localities 
indicate approximately the southeastern border of this mouse’s range which may 
thus extend north through Kansu to Siberia. The fact that at Tachiao it 
occurs together with undoubted examples of the smaller A. sylvaticus draco seems 
to indicate its specific distinctness from the latter. The coloration is decidedly 
paler than in the latter, between buff and ochraceous buff above finely lined 
throughout with black, especially on the mid-dorsal area; the tail is sharply 
bicolor even in the immature examples; the feet are white, and the under parts 
whitish, with the slaty bases of the hairs slightly showing through. The ears 
are conspicuously large, measuring in the dried skins from 18 to 20 mm., as 
against 15 and 16 for A. s. draco. 
The following measurements were made by the collector in the field: — 
Total 
No. Locality. Length. Tail. Hind Foot. 
7641 Lianghokow 230 113 27 
7642 Shuowlow 221 117 25 
7644 Shuowlow 220 110 27 
7643 Shuowlow 231 112 26 
7646 Tachiao 214 113 27 
7648  Tachiao 211 109 26 
Average (6) 221 112 26 
Radde gives total length 215; tail, by calculation, 97; hind foot 24. 
The skull is large, the teeth broad and heavy. The interorbital constriction 
is so great that the external faces of the molars can be seen when the skull is 
viewed from above. The supraorbital ridge extends backward to a point about 
opposite the posterior root of the zygomatic arch. The notch formed by the 
upper edge of the antorbital foramen is very much deeper in the long axis of the 
skull than in the skull of A. s. draco. The following cranial measurements are 
taken from No. 7644:— total length, 29.9; basal length, 23; palatal length, 
14.6; nasals, 12; incisive foramina, 6; upper diastema, 7.2; zygomatic breadth, 
