Contrast a coral and a siphonophore as two kinds of cnidarians that live as colonies. How does a veliger larva of a collect food differently than it will when it later metamorphoses into a juvenile creeping snail, for example on a rocky shore. Prosobranch snails are grazers, predators, suspension feeders. Featured Organism p. 77, Fig. Copepods are central to ocean food webs.
Life cycles reveal that all barnacles are crustaceans - and some parasites are barnacles.