Edited sentence: As in the gastropods, the veligers of bivalves may either eat plankton, or survive off yolk retained from the egg.Like gastropods, the veliger of bivalves typically follows a free-living trochophore stage.Many freshwater species go further, with the veliger also remaining within the egg, and only hatching after metamorphosing into the adult form.Shipworms, however, hatch directly as veligers, with the trochophore being an embryonic stage within the egg.Some species spend a considerable time searching for an ideal habitat before metamorphosing, but others may settle on the nearest suitable substrate.The shell of a bivalve veliger first appears as a single structure along the dorsal surface of the larva.The veliger attains the adult form when it sheds its velum.The velum projects from between the valves, in front of the small foot.This grows around the veliger's body, becoming folded into the two valves of the adult