EVOTOMYS 4Ol 
Characters :—With a few exceptions, they resemble typical 
Microtine, but are lighter, more elegantly built, and have the 
dorsal surface usually of some shade of rufous; deeper and 
richer in humid, wooded regions, lighter and yellower with a 
tendency to winter whitening in the north. The eyes and 
more or less circular ears tend to be more conspicuous than 
in Mucrotus; the feet are small, with normal pads; the tail 
is shorter than in murines, longer than in Mccrotus; the fur 
is long and soft in winter, shorter and harsher in summer. 
The mamme are 8, viz. 4 inguinal and 4 pectoral. 
The skull shows 
some murine charac- 
ters, being compara- 
tively weak, and 
lacking in angularity. 
The outlines are full 
and rounded, the 
ridges, even in old 
age, slightly devel- 
oped. The _inter- 
orbital region is 
broad, the auditory 
bullae large and com- 
paratively inflated. 
The zygomata are usually slender, and scarcely widened 
in the regions where the jugals and zygomatic processes of 
the maxillaries meet; the mandible is slender and weak. 
The bony palate lacks the sloping part of the posterior 
median ridge, and shows little trace of the lateral pits, 
both so characteristic of J/zcrvotus; it thus terminates in a 
thin-edged shelf continuous between the alveoli of the posterior 
cheek-teeth. This arrangement was at first thought to be 
highly characteristic, but has since been found in other genera, 
as Anteliomys and Eothenomys. 
The incisors are weak and slender, and those of the 
mandible run back, each along the lingual sides of its first and 
second cheek-teeth, crossing the tooth-row behind the latter, 
and terminating in the ascending ramus of the mandible 
distinctly below the dental foramen ; not rising above the level 

FIG. 60,—PALATE OF (A) Zvotomys ; (B) Microtus 
(diagrammatic and magnified). 
