Although 1500–3000 eggs were encapsulated in a capsule, only
less than 50 whelks hatched out. This trend may be explained by
the fact that capsules contain both fertilized and nutritive eggs, and
normal fertile eggs can absorb nutrients in the intracapsular fluid, as
well as digest additional nourishment from the extraembryonic yolk
in the nutritive eggs, a phenomenon documented for many species