" Upper arm" portion of a crab claw

Gills composed of thin plates, constructed like the pages of a book

"Forearm" portion of a crab claw

Small feeding appendage found in Chelicerates

External skeleton; the shell of a crustacean

Organisms that cannot swim or are very weak swimmers and are at the mercy of the currents

Muscular, segmented body part, posterior to the thorax; the edible "tail" portion of a lobster or shrimp

Number of individuals in a particular area

Segmented worm in Phylum Annelida; includes earthworms, marine worms, and leeches

Toward the head end; opposite of posterior