Porifera: sponges Cnidaria: anemones and soft corals Mollusca: snails, bivalves and squid Arthropoda: lobster and horseshoe crab Echinodermata: sea stars, urchins and sand dollars Chordata: sea squirts and tunicates Still others are considered completely inedible, yet are used by people in other manners (see the horseshoe crab). Some of them, like lobster and scallop, have become New England favorites while others, like squid and urchin, are sent to growing markets abroad. As fish stocks in the North Atlantic dwindle, fishing communities are turning to invertebrates as a commercial crop. In the species descriptions below, people may recognize creatures from visits to tidepools or the dinner plate. Currents nourish the younger life stages and distribute these organisms to the far flung reaches of their adult range. Many of the following species are quite familiar as attached creatures in their adult stages, yet most, marine invertebrates spend at least part of their life drifting on currents as zooplankton.

This, however, is a somewhat misleading definition. “Other invertebrates” is the term we use to distinguish a whole host of spineless animals that do not drift with the tides like plankton. Orange-footed sea cucumber and green sea urchins.

Do sponges have kegs to move