| endoskeleton | | the name of the shell that covers the cephalothorax |
| crustacea | | another name for the large digestive "tomali" in some crustaceans |
| carapace | | squids have two attached at the gills, one that supplies the rest of the body |
| medusa | | animals in this phylum have jointed appendages and a chitinous exoskeleton. |
| bivalvia | | another name for "losing your guts", especially in sea cucumbers |
| gastropoda | | a class of mollusk with animals that have a muscular foot and, in many cases, a spiral shell |
| molt | | when a sea star or arthropod replaces a lost appendage |
| planula | | the main body region of a crustacean |
| hepatopancreas | | the name of the first type of crab larvae |
| ambulacral | | the bell-shaped stage of a cnidarian |
| cephalopoda | | animals in this subphylum have two pairs of antennae, compound eyes and gills. |
| arthropoda | | the name of the sponge and cnidarian larvae |
| alternationofgenerations | | the description of the cnidarian life cycle which changes from medusa to polyp |
| aristotleslantern | | the appendages that make up the mouth of a crustacean |
| echinoidea | | a class of mollusk with 8 or more arms |
| eviscerate | | the name of the second type of crab larvae |
| tubefeet | | the animals in this mollusk class have two shells. |
| brittlestars | | the five large teeth found in sea urchins |
| gastric mill | | agile, scrawny sea stars in the class ophiuroidea |
| asteroidea | | in crustaceans, these are attached to the legs and are found under the carapace. |
| megalops | | in mollusks, a tongue with teeth |
| radula | | the "teeth" in the stomach of a crustacean |
| maxillipeds | | the class of echinderms that includes sand dollars and sea urchins |
| papillae | | the phylum of invertebrates that includes sea stars, urchins and sand dollars |
| echinodermata | | the shell-like endoskeleton of sea urchins |
| gills | | squids have eight arms and two of these longer appendages |
| cheliped | | the class name for sea cucumbers |
| cephalothorax | | the name for a skeleton found on the inside of organism |
| zoea | | the large claw-bearing appendages of crustaceans |
| tentacles | | these structures cut through the body walls of some echinoderms allowing them to respire |
| heart | | what crustaceans must do to grow a new exoskeleton |
| regenerate | | the class of echinoderms that includes sea stars |
| test | | the groove in which tubefeet of echinoderms are found |
| holothuroidea | | the dozens of suction-cups that allow echinoderms to crawl |
