a planktonic larval stage of certain species of molluscs, intermediate between the trochophore
and the adult form.

The animal shown above had a shell of approx 1mm. Those below were 2-3mm, with longer
velum up to 8mm. The velum is a ciliated swimming and feeding organ. When placed in a tank they
refused to extend the velum and began to crawl.

© All images Copyright 2021 Denis Riek. All rights reserved.