Abstract: 2.Dinophilidae (4) Dinophilus gyrociliatus O.Schmidt Dinophilus gyrociliatus O.Schmidt with sexual dimorphism,has been found in sediment at a depth of 200mm of the intertidal zone.This species was recorded for the first time from Chinese waters.Our specimens were obtained on 10th September,1964,when the temperature of sea water was 22℃.The worms were transferred into small dishes for culture.Three days after-wards one egg capsule was found (fig.10,C).The capsule looks like a deflated balloon with nine eggs inside,3 of which are small and may be the embryos of male.24 hours later,the egg capsule became large (fig.10,D).3 days later,four female juveniles were liberated from the,egg capsule,swim very actively in the culture dishes.There is a pair of red eyes (figs.10,E-F).The neotony female (fig.10,G) and the giant male (fig.10,H) Were hatched from the big eggs.but as they do not have any gut and are therefore short living.