Any larval gastropod or bivalve mollusk in the stage when it is furnished with one or two ciliated membranes for swimming.

the larval stage of a mollusk which is furnished with a velum or ciliated swimming membrane. When hatched, veligers are usually free-swimming but they may also be seen rotating within the egg capsule just prior to hatching.

pelagic, larval stage of some meroplanktonic molluscs (i.e., clams and snails)

Molluscan planktotrophic larva that supersedes the trochophore, and in which the shell, foot, velum and other structures make their appearance.

Second larval planktonic stage of molluscs where the foot, shell, and other structures first make their appearance.

A zebra mussel larva

Veliger are the free-swimming, planktonic larvae of certain marine and fresh-water univalve mollusks, or gastropods as well as some bivalves (Dreissena sp.). Swimming is accomplished by one or more ciliated membranes.