1903-9.] THE HABITS OF PLETHODON CINEREUS ERYTHR®NOTUS. 473 
eggs. That fertilization is internal, and that it precedes egg-laying 
by a considerable time may be inferred from the following. The female 
is provided with spermathecee which are already filled with sperma- 
tozoa at a time when the eggs are yet in the ovaries and have not attained 
a greater diameter than two mm. Quite likely the spermathece are 
filled long before this because at this time no spermatozoa are to be found 
in the genital tract of the male. ‘The testes are filled with spermatocytes 
Which as Mongomery (03) deseribes undergo their maturation during 
the summer; spermatozoa may be found after the middle of August. 
Further observations are necessary to determine whether transference 
occurs in autumn or in spring. 
Although there is a total lack of secondary sexual characters it is 
usually possible to distinguish between the sexes owing to the thinness 
and translucency of the muscle and skin. Because of the dark colour 
of the testis and the light colour of the eggs the posterior part of the ab- 
domen when viewed from beneath is dark or light according as the speci- 
men is male or female. This distinction is most evident in the spring, 
the eggs being largest at that time but in most cases it can be made at 
any season. In addition, the cloacal glands of the male cause a whiteness 
and a swelling at the sides of the body just behind the posterior limbs. 
There is considerable latitude for a Urodele in the time at which egg- 
laying occurs. ‘The earliest date on which eggs have been found was 
June 16th—3 clusters, the eggs in early stages of segmentation; the 
latest is July 3rd—1 cluster, in the same condition. The difference is 
not due entirely to different seasons being early or late, nor to one bit 
of woodland being better sheltered and warmer than another, for clusters 
of eggs with the females on guard and other females with the season’s 
eggs yet in the ovaries have been found in the same log on the same 
day. The date, Oct. 25th, given by Sherwood (’95) for the finding of 
eggs of Plethodon is not accompanied by any description of them ; and 
its exceptional lateness leaves the meaning of his observation doubtful. 
The eggs of the one individual seem to be deposited all at the one time. 
No female was found guarding a cluster of eggs having also any in the ovi- 
duct or even in the ovary that were nearly full size. It is however not at 
all uncommon to find an egg in one ovary about half-size; this should be 
associated with the small egg of some bunches described below and con- 
sidered as one that should have been laid this season but which, having 
failed to develop its proper amount of yolk, is retained in the ovary. 
As asituation for the eggs marked preference is shown for logs almost 
entirely embedded in the humus, logs that have decayed to a point where 
the substance is friable with large cracks running lengthwise. In one 
