The Robinson Library >> Science >> Zoology >> Phylum Porifera
About the Phylum Porifera

The word "porifera" comes from the Latin porus, or pore, plus ferre, to bear. The word refers to the fact that the surface of a sponge's body is covered with tiny pores. With neither true tissues nor organs, sponges are the most primitive of multicellular animals.

simplified diagram of a sponge

The body of a sponge is permeated with flagella-lined openings through which water is swept and food particles and oxygen extracted. All sponges are stationary as adults. Some species are as small as 1/4 of an inch, while some grow to six feet or more. The majority of sponges live in the ocean, but there are a few that inhabit fresh water. Sponges have remarkable powers of regeneration; even if much of the body breaks or is cut away, the sponge can replace the broken parts.

Class Demospongiae -- horn sponges -- This class has the greatest number of sponge species and includes the familiar household varieties as well as brilliantly colored fans, vases or spreading branches. These sponges can have glass spicules, spongin fibers, or both types of skeletal materials.

drawing of the dead men's fingers sponge

Class Hexactinellida -- glass sponges -- Skeletons composed of six-pointed bits of silica that in many species are formed into elaborate lattices like those of the Venus' flower-basket.

drawing of the Venus' flower basket sponge

Class Calcarea -- All these sponges are small, with skeletons of calcium carbonate. Some are vase-shaped; others are irregular.

drawing of a tufted sponge

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The Robinson Library >> Science >> Zoology >> Phylum Porifera

This page was last updated on 06/16/2017.