ed in some individuals no longer having juvenal pelage;
some new pelage was observed on the skins of seven mice collected in
August. Each of these was in category 4 or 5 and probably had been born
in the previous calendar year. These seven molting individuals make up
nearly 17 per cent of 42 individuals that had completed the juvenal to
postjuvenal molt. In November, 80 per cent of individuals (92 of 115)
that had previously obtained their postjuvenal or adult pelage were
molting. These mice were in age-categories 3, 4, and 5. Some of the
individuals in category 3 were developing new hair beneath a relatively
unworn bright pelage that I judge to be an adult pelage rather than a
postjuvenal pelage. If this judgment be correct and if the relatively
unworn dentition (category 3) means that these animals are young of the
year, we must conclude that individuals born in early summer may molt
from juvenal to postjuvenal, then to adult pelage, and finally in the
autumn into another adult pelage. Other individuals, six in number and
of categories 2 and 3, are simultaneously completing the juvenal to
postjuvenal molt and beginning the postjuvenal to adult molt. The
juvenal to postjuvenal molt begins, as has been described by various
authors, along the lateral line and proceeds dorsally and ventrally and
anteriorly and posteriorly, and the last patch to lose the gray juvenal
color is the top of head and nape, or less frequently the rump. In some
individuals a gray patch on the nape remained but emerging hair was not
apparent; perhaps the molt had been halted just prior to completion. The
progressing band of emerging hair is narrow in most specimens but in
some up to one-fifth of the circumference of the body has hair at the
same degree of emergence. Subsequent molts, both from postjuvenal to
adult pelage and between adult pelages, are less regular in point, or
points, of origin, width of progressing molt, and amount of surface
molting at one time. Half or more of the dorsum is oftentimes involved
in the same stage of molt at once. In some specimens the molt begins
along the lateral line, and in others in several centers on the sides.
In some skins distinct lines of molt are visible without parting the
hair, and in some others the molt is patchy in appearance. Growth of new
hair is apparent at various times of the year as a result of injury such
as that caused by bot fly larvae, cuts, scratches, or bites of other
mice. Abrasion, wear