Adductor muscle
- the muscles of a bivalve that work to keep the two halves closed tightly; shell will open when muscles relax

Anesthetize - sedate; to calm or quiet

Aperture - opening of shell through which the animal can protrude

Apex - the pointed tip of a gastropods shell where growth begins

Axial - situated around or along an axis or a central line

Beak - the point of the shells where they meet at the hinge; also called umbo

Bivalve - also called Pelecypoda; mollusk with a two-part shell including clams, oysters, mussels, and scallops; shells attached by hinge; no head or radula

Body whorl - largest coil containing body

Brackish - somewhat salty

Byssus - byssal threads; thin fibers produced by the byssal gland in the foot of some bivalves, which attach the animal to a stationary object

Camouflage - to disguise and match with surroundings

Cannibalistic - the act of eating the same species

Carnivores - meat-eaters; animals that feed on other animals

Carrion - dead and decaying flesh

Chemoreceptor - a sense organ that receives chemical signals from surroundings

Colonize - to establish or settle in a colony or group

Commensal - friendly; no harm to either individual

Concentric - having a common center; going to the same place; circling

Deposit feeders - animals that feed on organic matter in the sediment

Detritivores - detritus (broken down plant and animal material) eaters

Detritus - tiny pieces of broken down animal and plant material suspended in water

Echinoderm - group of marine animals with stiff spiny body walls (sea urchins, sand dollars, and sea stars)

Environments - all factors (physical, chemical, and biological) affecting the life of an organism or community

Equivalve - having equal halves

Foot - the fleshy part of a mollusk that aids in movement

Herbivores - plant-eaters

Hermaphrodites - either a change of sex or sexual flexibility; can be both male and female at the same time

Hinge - where the shell halves connect; attached by a ligament

Intertidal - being exposed at low tide and covered at high tide

Larvae - single larva; immature form of an animal that changes shape before becoming an adult

Ligament - the connective tissue between the two halves of the shell that allows for opening

Linear - consisting of a straight line

Lip - the edge of the shell bordering the aperture

Mantle - the membrane in a mollusk that surrounds the soft body parts; secretes calcareous shell

Mantle Cavity - the open space surrounding mantle

- small; can only be seen through a microscope

- An invertebrate animal belonging to the phylum Mollusca. All members have soft bodies that are covered by a thick membrane called the mantle. Many mollusks secrete calcareous shells; others do not.

- those that eat both plant and animal material

- lid-like covering in gastropods closing aperture when mollusk pulls inside

- a thin, outer layer covering some shells; can be smooth or hairy; is usually scrubbed off by waves and sediment when the animal dies

Periphery - the border of a rounded object

- floating or swimming animals and plants in a body of water

Predate - the act of killing and consuming animals

Predator - one that kills and consumes animals

Prey - the animal that is killed and consumed

Proboscis - a tubelike extension including a mouth and a radula

Radial - coming from a common center; arranged like spokes

Radula - a ribbonlike toothed appendage used to bore, saw, tear, or scrape depending on the feeding habits of that particular species

Scavenge - the act of collecting and eating dead plants and animals

- those that collect and eat dead material

Sedentary - characterized by or requiring much sitting; still

Sessile - permanently attached; immobile

Siphons - tubes or openings where water enters or is pushed out

Spat - the young of a bivalve mollusk

Spawning - to produce eggs or offspring in large numbers

Spire - part of shell containing all whorls leading to a point called the apex

Suspension feeders - animals that get their food, which are tiny floating particles of organic material, from the water around them

Sutures - a seam or line along which two things or parts are joined

Tactile - sense of touch

Tentacle - a long flexible projection near or on head

Tests - hard shell-like covering of some echinoderms

Umbo - the hinged end; also called beak

- also called gastropod; mollusk covered by a one-part shell

Valve - another name for shell

Whorl - each coil of a univalves shell

Zooplankton - animal plankton