he smaller North American species of _Sorex_. From _S.
merriami_ of southeastern Wyoming, it differs in having a shorter, much
shallower dentary, a shorter molar row, and a lower coronoid. In every
particular it is identical with _Sorex cinereus_. _Sorex cinereus_ from
northern British Columbia and the specimen from Nuevo Leon differ from
_Sorex saussurei_, _S. obscurus_, and _S. vagrans_ in the ratio of the
height of the coronoid to the length of the dentary. This ratio
averages 49.6% in _S. cinereus_ and 53.0% or more (up to 60.0%) in the
other species. _Microsorex hoyi_ differs from _S. cinereus_ and from
the specimen in question in deeper and shorter dentary, more robust
condyle, dentary less bowed dorsally, molars shorter in anteroposterior
diameter and higher in proportion to this dimension.

This record, as far as I can determine, constitutes a southward
extension of the known Pleistocene or Recent range of this species of
approximately 800 miles. The nearest known occurrence of _S. cinereus_
in Recent times is in the mountains of north-central New Mexico. The
species now has an extensive range in boreal North America and prefers
mesic and hydric communities from which it rarely wanders. I know of no
instance of the occurrence of the cinereous shrew in desert areas such
as there are between many of the mountain ranges of southern New
Mexico, Coahuila, and Nuevo Leon. Therefore, unless the habitat
preferences of the species have changed since Pleistocene times, this
find constitutes additional evidence that more humid conditions at one
time prevailed in the regions mentioned.

Sorex saussurei Merriam

Fragments of three other specimens of _Sorex_ occur in the collection.
One of these is a right ramus, C. I. T. No. 3943, and is complete
except for the canine. The other two bear no numbers and I have
designated them "A" and "B." "A" is a left ramus with the dentary
broken off anterior to the canine and bears p4 and the canine. "B" is a
right ramus bearing m2 and the roots of m3 and is broken off at the
middle of the alveolus of m1. Each specimen has certain peculiarities
but they resemble one another so closely that I regard all three as of
the same species. The teeth, where comparable, are of essentially the
same size and configuration. The horizontal rami of the dentaries are
the same. The fossils differ, however, in the configuration of the
coronoid process. In No. 3943 the coronoid is robust and inclined
an