The early development of P. viridis has been described by Tan (1975), Rao et al. (1976) and
Sreenivasan et al. (1988). The spawned eggs of P. viridis become spherical and after fertilization cleavage takes place. About 7 –8 h after fertilization, the blastula transforms into a mobile, trochophore larva (Siddall 1980; Rajagopal 1991).The veliger larval stage is developed after 16 –19 h when it has a shell covering the internal body parts and a strong ciliated velum (Sivalingam 1977). The larvae secrete the initial byssal threads in 10 – 12 days and remain in plankton for another 15 – 20 days (Siddall 1980), until they find a suitable
substratum (Sivalingam 1977; Appukuttan et al. 1984; Rajagopal 1997). Plantigrades attach to a
variety of natural objects using byssus threads and are transported far and wide (Hicks et al. 2001).