Larval development of Marphysa gravelyi (Polychaeta: Eunicidae) from Pulicat Lake, India

The larval development of Marphysa gravelyi (Polychaeta: Eunicidae) from Pulicat Lake, South India, was studied using light and scanning electron microscopy. The adults of M. gravelyi have an elongated, reddish-brown body and live inside burrows in the muddy bottom of the lake. They produce benthic jelly masses in which the embryos occupy the core and are protected until the completion of larval development. Four different larval stages were observed: prototrochophore, early metatrochophore, late metatrochophore and nectochaeta. These lecithotrophic larvae are found to be swimming inside the jelly mass. The larval development is completed in 8–10 days. Synchrony was observed in the development of larvae inside the jelly mass. Larval settlement begins after the nectochaeta stage.