The plantigrade is an attached larval stage and typically measures less than 500 µm in its longest dimension. In contrast to previous larval stages that possessed a velum for feeding and swimming, the mussel now feeds using gills, which occupy most of the mantle cavity, and moves solely with its foot. Labial palps develop around the mouth. Further metamorphosis transforms the plantigrade larva into a juvenile zebra mussel, thus completing the larval phase of the life cycle.
