980 
Journal of Agricultural Research 
Vol. XXVIII, No. 10 
COLORATION 
Microtus m. montanus and the subspecies yosemite average slightly darker than 
the general run of western meadow mice. The pelage is of the usual agouti 
pattern, but its precise color is not of interest here. 
Although there is quite a bit of variation in the shade of the pelage among the 
males, this is not sufficient to make it easy to divide the series of this sex into two 
lots based on shade alone. They may, however, very readily be divided into two 
groups, one of which has an appearance rather dilapidated, this being in part due 
to wear, but to a greater extent to an uneven appearance which may be ascribed 
to fighting among themselves, as well as to the great prominence of the hip glands. 
The other group differs considerably in appearance, for although the glands in 
the larger individuals of this series are just as prominent as in some of the other 
lot, the skins have a sleeker look, are but little worn, and show practically no 
sign of fighting. 
Of this second group, one specimen is a large, fully adult male in unworn- 
looking coat, but the remainder are smaller animals which are readily classed 
as subadults, sexually adult, except in three cases. These latter have a distinct 
look of immaturity, which consists of an appearance of shortness and compactness 
of the pelage of the entire body. The largest of these three, though still largely 
in the juvenile coat, is labeled as being sexually mature; but the other two are 
definitely juvenile. The pelage of none of these males is excessively worn. 
Four of the females have the dorsal surface excessively worn, this being almost 
black in places. Severe wear results in the tips of a varying proportion of the 
hairs of the back breaking off, thus exposing to a greater or lesser extent the 
dark, plumbeous bases. There is considerably more variation of color in the 
remainder of the female than in the male series, and it is easy to divide them, 
according to shade, into two well-marked groups, although there are many 
intermediate examples the allocation of which is arbitrary. One group, very 
uniform, is of a brighter shade of brownish than the male series. A few of the 
males have counterparts in shade among the brighter females, but there are a 
number of the latter brighter than any of the males. The other group of females 
is exceedingly variable. Although it contains many individuals which might 
really, with equal propriety, be placed in the “bright-colored group,” the series 
consists essentially of skins with a definitely more grayish cast, rather than a 
brownish one. The variation present is largely in the amount of gray. The 
larger, older females are for the most part paler and grayer than are any of the 
males and are rather uniform in this respect. The larger subadults are more 
variable, some of them being a trifle more brownish, while others are of a darker 
gray than the adults, due to an admixture of a greater number of black-tipped 
hairs. The whole “gray ” series grades down to seven individuals which have the 
appearance of immaturity, being darker dorsally, with shorter, more compact 
pelage; but only the smallest specimen is definitely juvenile, for five of the 
remaining six contained embryos. There are a number of specimens, however, 
which, although with shorter head and body measurements than some of these 
six, have the type of pelage of the older animals. 
In general, the largest specimens have the longest coats, but unless this be new, 
the hairs of the ventral surface are not relatively longer. Subadults in sleek 
pelage, even though this be rather short, normally have the longest hairs upon the 
underparts, and this surface is then correspondingly paler than in the case of 
individuals in which there has been wearing away of the pale hair tips. Similarly, 
specimens with palest underparts have a scanty growth of palish hairs upon the 
under side of the tails, which when worn away, leaves the tail almost black both 
above and below. The skin of the feet is uniformly sooty, but the hairs growing 
