Trochophore

The anatomy of a trochophore
A - episphere
B - hyposphere
1 - ganglia
2 - apical tuft
3 - prototroch
4 - metatroch
5 - nephridium
6 - anus
7 - protonephridia
8 - gastrointestinal tract
9 - buccal opening
10 - blastocoele

Bright-field microscope image of trochophore of annelid Pomatoceros lamarckii (family Serpulidae)

A trochophore (/ˈtrɒkoʊfɔər/; 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. Additionally, in this way they bring their food closer, in order to capture it more easily.

Occurrence

Trochophores exist as a larval form within the trochozoan clade, which include the entoprocts, molluscs, annelids, echiurans, sipunculans and nemerteans. Together, these phyla make up part of the Lophotrochozoa; it is possible that trochophore larvae were present in the life cycle of the group's common ancestor.

Feeding habits

Trochophore larvae are often planktotrophic; that is, they feed on plankton.

Life cycle

SEM

Image of development of the annelid Pomatoceros lamarckii (family Serpulidae) showing the trochophore in images D-F

D - early trochophore
E - complete trochophore
F - late trochophore
G - metatrochophore

9-hour-old trochophore of the marine gastropod Haliotis asinina
sf - shell field