A Contribution to Our Knowledge of the Life History of Arenicola Marina L.

Abstract

The breeding season of the lugworms of the Whitstable area is a sharply defined one, extending for 14 days between the new moon and full moon spring tides in the second half of October. Spawning begins slowly and reaches a maximum at the intervening neap tides and then declines in intensity.Both eggs and sperms are discharged from the burrows at extreme low water to lie on the surface of the sand. Here fertilization occurs.No germ cells were detected in the body cavity from November to June, but from August onwards to the end of October 98% of the adult worms are ripe.At the end of the spawning period about 40% of the adults die.A brief description of gametogenesis and of the mature gametes is given.Germ cells are discharged through the nephridia.