ailed shrew. 1.

_Peromyscus leucopus noveboracensis._ Northern white-footed
mouse. 2.

_Rattus norvegicus._ Norway rat. 4.

_Mus musculus musculus._ House mouse. 22.

_Sylvilagus floridanus mearnsii._ Mearns cottontail. 2.

From time to time a few traps were set in the old farmhouse and in the
barn and other outbuildings of our camp. In these buildings northern
white-footed mice, Norway rats, and house mice were taken. Several
cottontails were seen in and under the old barn. The Helming boys
trapped a short-tailed shrew and also house mice and a white-footed
mouse in the basement of their house.

RECORDS OF THE NUMBER OF EMBRYOS

All the females taken were examined for embryos, and the results are
here tabulated by species and dates. The term _subadult_ is used to
indicate an individual which has reached adult size, but which is
still immature as shown by the pelage, unworn condition of the teeth,
and weakness of the skull sutures. For each individual the age is
first stated, next the number of embryos if any, and last the length
of the embryos in millimeters measured as they lie rolled in the fetal
membranes. For embryos too small to measure with field equipment the
term _small_ is applied.

These records indicate the breeding period of the different species
and the number of young.

_Mephitis nigra._ Eastern skunk

August 19: subadult, 0 embryos.

_Peromyscus leucopus noveboracensis._ Northern white-footed mouse

July 16: adult, 3 embryos, size small.
July 21: adult, 0; adult, 0.
July 22: adult, 5, 10 5 mm.; subadult, 0.
July 23: subadult, 0.
July 25: juvenile, 0, juvenile, 0; juvenile 0; subadult, 3, small.
July 30: adult, 0; adult, 0; adult, 0; subadult, 0.
August 2: adult, 0; subadult, 2, small; subadult, 0; subadult, 0.
August 5: adult, 5, small; subadult, 0.
August 23: subadult, 0; adult, 5, 10 mm.
August 24: adult, 5, 8 mm.; adult, 0; adult, 0; adult, 3, small.
August 25: adult, 5, 23 mm.; adult, 0; adult, 4, small; adult, 3,
small.
August 26: subadult, 4, 8 mm.; adult, 0.
August 29: adult, 4, 17 mm.

_Peromyscus maniculatus bairdii._ Prairie white-footed mouse

August 7: subadult, 0.
August 10: adult, 5, 8 mm.
August 13: adult, 3, 8 mm.; adult, 0.
August 20: adult, 5, small.
August 28: adult, 4, 17 mm.; adult, 4, 13 mm.
August 29: adult, 5, 17 mm.
August 30