The purple murex

breeds about springtime, and the ceryx at the
close of the winter. And, as a general rule, the testaceans are
found to be furnished with their so-called eggs in spring-time and
in autumn, with the exception of the edible urchin; for this animal
has the so-called eggs in most abundance in these seasons, but at no
season is unfurnished with them; and it is furnished with them in
especial abundance in warm weather or when a full moon is in the
sky. Only, by the way, these remarks do not apply to the sea-urchin
found in the Pyrrhaean Straits, for this urchin is at its best for
table purposes in the winter; and these urchins are small but full
of eggs.

Snails are found by observations to become in all cases
impregnated about the same season.