STUDIES ON THE TURBELLARIA. 449 
egos on the bottom of the vessel. I have never witnessed the 
act of oviposition, and it probably takes place during the 
night. Solitary eges are occasionally found; but, as a rule, 
a varying number—sometimes as many as thirty—are found 
enclosed together in a transparent capsule adhering to the 
glass. The capsule is structureless with, frequently, included 
foreign bodies, such as unicellular Algze. Often spermatozoa 
of the animal are embedded init. The individuals from which 
those eggs were discharged were found not to be ruptured in 
any way, and there seems to me to be little doubt, that the 
egos pass out through the female aperture, and that the sub- 
stance of the capsule consists of the secretion of the unicellular 
glands opening into the antrum femininum. 
A remarkable point is that the reproductive apparatus is 
entirely absent during the winter. In specimens collected in 
April it was found to be intact, and in many there were 
fertilised ova. In the latter symptoms of degeneration 
showed themselves, however, most containing large vacuoles 
in the cytoplasm, though the nuclear spindles were still 
intact. But in June, July, and August none of the specimens 
examined showed any trace of reproductive apertures, and 
the examination of sections of a number showed not only 
that the apertures were completely absent, but that there was 
no vestige of reproductive apparatus, either gonads or ducts. 
These were full-grown specimens, resembling in every other 
respect those found two months before to contain mature 
sexual organs. Whether this means that the reproductive 
system becomes completely absorbed in the winter, to be 
regenerated in the spring, or whether it is that the generation 
which was sexually mature in April had perished, and a new 
generation had become fully grown without showing any 
rudiments of the gonads or their ducts, still remains to be 
determined. 
