What is "veliger"

Veliger \Vel"i*ger\, n. [NL., fr. L. velum a veil + gerere bear.] (Zo["o]l.) Any larval gastropod or bivalve mollusk in the state when it is furnished with one or two ciliated membranes for swimming.

n. (context zoology English) The planktonic larva of many kinds of marine and freshwater gastropod molluscs, as well as most bivalve molluscs.

A veliger is the planktonic larva of many kinds of sea snails and freshwater snails, as well as most bivalve molluscs (clams) and tusk shells.