Biology
Parts of the anatomy of Echinolittorina placida: head, penis and egg capsule. The glands of the penis produce mucus that aids attachment to the female during copulation.
The sexes are separate. During copulation the male mounts the shell of the female and inserts the penis under the lip of her shell and into the pallial oviduct. Mating may last for several hours. Sperm are transferred to the copulatory bursa, and later pass to another storage sac, the seminal receptacle, where they can survive for many months.
Females spawn several thousand transparent, drum-shaped egg capsules (0.26mm in diameter ), each sculptured with 3 concentric rings and containing a single egg. These are carried away by the tide, and rapidly hatch into swimming veliger larvae.
Larval development probably takes about 3 weeks, after which the larvae settle from the plankton onto a suitable hard substrate, and metamorphose into juvenile snails.
Growth is probably rapid and adult size is likely to be reached within a year, by extrapolation from other tropical Echinolittorina species.
