EGG CAPSULES AND DEVELOPMENT OF PRUNUM-PRUNUM (GMELIN, 1791) (PROSOBRANCHIA, MARGINELLIDAE) FROM THE VENEZUELAN CARIBBEAN

Prunum prunum, a common marginellid of Venezuelan sandy beaches has a piano-convex egg capsule that is attached to the substrate by an oval base. An ellipsoidal suture at the middle top of the egg capsule could act as a preformed escape aperture. A single, large, bright yellow eg g develops within each egg capsule. The egg measures between 0.895 and 1.075 mm in diameter, being the largest egg recorded for the Marginel lidae. Hatching takes place as a crawling juvenile, 55-60 days after o viposition. The shell length at hatching is 2.7 to 3.0 mm. Differences in protein and carbohydrate concentrations in the intracapsular fluid between early and pre-hatching stages suggest that, despite the enorm ous amount of yolk contained in the egg, the embryo may require extrae mbryonic food to complete development.