And, as a general rule, the testaceans are found to be furnished with their so called eggs in springtime 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 except for the sea urchin found in the Pyrrhaean Straits, for this urchin is at its best in the winter; and these urchins are small but full of eggs.