Biology Chapter 21 (pages 443-454)

31 terms by sarahsquiz

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soft-bodied, boneless water creatures


used for locomotion

visceral hump

contains internal organs


a skinlike organ which covers the visceral hump, and in most species, produces a calcium carbonate shell for protection


when nacre builds up around an irritant

adductor muscles

the hinges that hold together the two shells of a bivalve mollusk

mantle cavity

open chamber in which the gills are located

incurrent siphon

takes water into the mantle cavity to the gills

excurrent siphon

where water that has passed through the incurrent siphon exits the body


also called univalves - have a single shell


gastropods which look like snails without shells


sea creatures which have brilliant colors and elaborate plumelike gills




a rough, file-like organ in mouth that scrapes food and carries it like a conveyor belt into the digestive tract

giant squid

largest invertebrate


only cephalopod with an external shell


spiny-skinned sea animals

watervascular system

a complex system of water-filled tubes that extends throughout the body


the arms of starfish


at the end of each starfish ray

tube feet

on the underside of starfish rays; appear in two double rows


microscopic invertebrates found in freshwater lakes and ponds


eggs that require no fertilization


stinging cells


a cylindrical body type for coelenterates


a free-swimming, umbrella-shaped body type which has its mouth facing downwards

sea anemone

"flower" of the ocean


colonial coelenterate

coral reefs

when limestone cups of many corals eventually form together into these limestone structures

excurrent pore

the opening by which water leaves a sponge

incurrent pores

the tiny openings by which water enters a sponge

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