Next Question 3. An operculum is a snail s trapdoor . The antennae on a mollusk are called tentacles. Next Question 2. Pupa is not a development phase of mollusks.
All mollusks come from eggs.
Some are live-born and some hatch from eggs externally. After they hatch from the egg, the development of mollusks varies. A trochophore is a multicellular larval stage of most mollusks. A veliger is freely swimming mollusk larva. Next Question 1.