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)