Trochophore, also called trochosphere, small, translucent, free-swimming larva characteristic of marine annelids and most groups of mollusks. Trochophores are spherical or pear-shaped and are girdled by a ring of cilia (minute hairlike structures), the prototroch, that enables them to swim.

How does a trochophore move through water?

A trochophore (/ˈtroʊkəˌfɔːr, ˈtrɒ-, -koʊ-/; also spelled trocophore) is a type of free-swimming planktonic marine larva with several bands of cilia. By moving their cilia rapidly, a water eddy is created. In this way they control the direction of their movement.

Do all mollusks have trochophore larvae?

Molluscs include such familiar creatures as clams, oysters, snails, and octopi. They share a distant common ancestor with the annelid worms, an evolutionary heritage suggested by their larval form, called a trochophore larva, found in all molluscs and in certain marine annelids called polychaete worms.