MICROTUS. 301 
mamme four to eight, two or four pectoral and two or four inguinal; 
normal number eight; plantar tubercles six; soles moderately hairy. 
KEY TO'SPECIES AND SUBSPECIES OF THE SUBGENUS. 
A. Size small. (Mamme four.) 
a, Above dark brown and black; beneath chest- PAGE 
i STALE SIDR, oo ok ya al ar M. fulviventer 301 
b. Above mixed cinnamon; beneath buffy.....M.mexicanus 301 
c. Above bistre and black; beneath plumbeous, 
suied I 3G0 Aigayel igre haz)” 5 Ve eee eat M.m. pheus 302 
B. Size large. (Mamme eight.) 
Bee MOVE CAnK GANIC eo 0 tio. i... eas M.c. hyperythrus 302 
303. fulviventer (Microtus), Merr., Proc. Biol. Soc. Wash., xu, 
1898, p. 106. 
FULVOUS-BELLIED MEADOW VOLE. 
Type locality. Cerro San Felipe, State of Oaxaca, Mexico. Alti- 
tude, 10,200 feet. 
Geogr. Distr. State of Oaxaca, Mexico. 
Genl. Char. Similar to M. mexicanus, but redder. 
Color. Above dark brown and black; under parts chestnut ful- 
vous; tail blackish above, pale fulvous beneath. 
Measurements. Total length, 154; tail vertebrae, 38; hind foot, 
20. Skull: basal length, 25.4; length of nasals, 7.4; zygomatic width, 
15.5; mastoid breadth, 12.4; length of upper molar series, alveolar 
border, 6.5. 
304. mexicanus (Hemiotomys), Sauss., Rev. Mag. Zoél., 2me Sér., 
LOOM eae 
Mexican MeEapow VOLE. 
Type locality. Mount Orizaba, State of Puebla, Mexico. 
Geogr. Distr. Eastern part of State of Puebla, Mexico. 
Genl. Char. Size small; tail short; ears large. Skull broad; incisive 
foramina wide and short; first lower molar with six interior salient 
angles; mammee four, two inguinal, two pectoral. 
Color. Above mixed cinnamon and black, paler on sides; beneath 
buffy; sides of nose cinnamon; tail above dusky, gray below; feet 
gray. The above is properly the winter pelage, that of summer 
being darker. 
Measurements. Average of 1o adults: Total length, 138; tail 
vertebre, 29; hind foot, 19.35; maximum, 148; 30; 20. Skull: basal 
length, 24.5; zygomatic breadth, 15.3; mastoid width, 11.6; length 
of nasals, 7.4; length of upper tooth row, alveolar border, 6.6. 
(Bailey, N. Am. Faun., No. 17.) 
