Feb., 1910.] 
Ohio Species of Mice. 
69 
sleeker and smaller in size and the tail is only about half as long 
as in that species. While collecting in Madison county a colony 
of the northern pine mouse was found in a pasture where the 
grass had grown rather high. As this was the 20th of November 
preparations had been made for winter evidently. I could not 
determine the number of specimens in the colony, but four of 
different ages were taken and there were evidences of others. 
Their nest was located under a split log lying with the flat side 
down and was composed of a quantity of soft grass with evidences 
of food material here and there. Runways led from the nest in 
various directions so that the mice had easy access to a supply 
of roots and other vegetable food in the vicinity. One of the 
specimens taken, a male, is adult and fully colored, a second 
specimen, also a male, is nearly adult size but the pelage is that 
of an immature individual, the other two are immature, not 
more than half grown. 
Synaptomys cooperi Baird. Cooper Mouse. This species 
even has a shorter tail than the pine mouse and differs from all 
mice of the genus Microtus in having the upper front teeth 
groved. The species in the field has a grayish appearance with 
the under parts clearly" lighter. It is quite widely distributed 
in the state and in places is common. It occurs in nearly^ the 
same situations as the meadow mouse and in one field at London, 
Madison county’, all three of the short-tailed mice here considered 
were taken on the same date and within the space of a few 
square rods. In Summit county I located a nest of this species 
on top of the ground and anchored in a bunch of clover. This 
nest only contained two young which were observed often until 
they grew large enough to run; two young is common in the 
species which would indicate that it is not as prolific as the 
meadow mouse. The species is met with commonly by T turning 
logs in fields and thin woods but is not confined to such situations. 
Peromyscus leucopus noveboracensis (Fisher). Common 
White-footed Mouse. There are at least thirteen variations of 
P. leucopus recognized and named from different parts of North 
America. Most of eastern United States is included within this 
range and subspecies reach Arizona, Montana and Yucatan. The 
species was described by r Rafinesque from specimens taken in 
western Kentucky’, a region where two forms appear to inter- 
grade making it necessary to apply the species name to specimens 
that are to some extent intermediate. Rafinesque’s name has 
been applied to the form which has the more southern range 
while the form that is uniformly distributed over Ohio is given 
the subspecies name noveboracensis. Recently Osgood has pub- 
lished an exhaustive treatment of the genus Peromyscus giving 
full information regarding all subspecies. This paper is one of 
