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Aquatic, sessile invertebrates that have no true tissues or organs that make up the phylum Porifera.


Describes an organism that remains attached to a surface for its entire life and does not move.


Collar cells; Flagellate cells that line the cavities of a sponge and draw water into the sponge by beating their flagella.


A pore in the body wall of a sponge.


An opening at the top of the sponge; where water leaves in a sponge.


Tough, flexible protein fibers; what some sponge skeletons are made of.


Tiny, hard particles of calcium carbonate or silicon dioxide that are often shaped like spikes; what some sponge skeletons are made of.

filter feeding

A method of feeding in which an aquatic animal traps organic material that is floating in the surrounding water; how sponges feed.


Cells which crawl about within the body wall of a sponge that distribute nutrients throughout the body.


Asexually produced internal buds that some freshwater sponges create during poor conditions. Food-filled balls of amoebocytes surrounded by a protective coat made of organic material and spicules that can survive harsh conditions.


The regrowth of missing cells, tissues, or organs.


Organisms that produce both eggs and sperm.


Bell-shaped body form of a cnidarian that is specialized for swimming.


Vase-shaped body form of a cnidarian that is specialized for a sessile existence.


The outer cell layer of a cnidarian.


The inner cell layer of a cnidarian.


A jellylike material between the epidermis and gastrodermis of a cnidarian.

gastrovascular cavity

The hollow gut in the center of the body of a cnidarian which has a single opening, or mouth.


Numerous flexible extensions surrounding the mouth of a cnidarian.


Specialized cells used for defense and capturing prey.


A cnidocyte organelle which has a long filament coiled up inside it.

nerve net

A diffuse web of interconnected nerve cells of a cnidarian.


A ciliated larva that develops from the blastula of a scyphozoan.

coral reefs

Large, rocklike formations built up from anthozoan polyps.


Cells of ctenophores which secrete a sticky substance that binds to their prey.

apical organ

A sensory structure at one end of a ctenophore's body that enables ctenophores to sense their orientation in the water.


The production of light by means of a chemical reaction.

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