Phylum Proifera - Sponges

Sponges are sessile animals that grow attached to shells, stones, and other hard objects on the bottom. The living animal is formed of simply organized cells usually supported by a skeleton of fibers called spongin and calcareous or siliceous spicules, spicules alone, spongin alone, or it may have no skeletal structures. The outer skin is often verytough but is permeated by small pores through which water is pumped into the animal to filter out microscopic-sized food. The water is discharged through larger pores or holes called oscula. Reproduction is by fragmentation, budding, or the production of eggs and sperm. The sponges found cast onto the beach are but the skeletons of former living animals and bear little resemblance to living sponges. Sponges are often amorphous with no distint shape but some species grow in regular patterns. Thus identification usually requires microscopic examination of spicule preparations; only those species with characteristic growth patterns can be determined by eye alone. Sponges grow in all types of havitats from intertidal rocks to the deep sea. Most are of no commercial value, but bath sponges are much sought after, being takenby hand with sponge hooks on long poles or by divers. Cleaned natural sponges still demand high prices in the markets; for many purposes they cannot be replaced by synthetics. All though there are several classes of sponges, only Class Demospongea is treated here. Class Demospongea These sponges exhibit a great variety of shapes, sizes and coloration. The skeleton may consist of spongin, siliceous spicules, both, or neither. There is a number of orders. Please note any brightly colored sponge has a posionous toxin which should never be touched. The sponge fauna of the northwestern Gulf of Mexico is not diverse, probably due to a combination of the cold winters and reduced salinities. Sponges are much more prevalent in the eastern Gulf, especially where coral reefs are found. Sponges common to the Northwestern Gulf Coast are boring sponges, which may be found in snail, clam and oyster shells.