In fact there is quite a variation in complexity in syconoid sponges. However, the body wall is generally thicker and more complex with incurrent canals rather than simple pores. Syconoid sponges appear to be larger versions (with more infoldings) of asconoids, still having just a single osculum. Note that water enters the sponge through a modified cell known as a porocyte. Choanocyte flagella create the current to expel it through a single osculum. Small and tube shaped, water enters the sponge through dermal pores and flows into the atrium. Most sponges fall into one of three categories, based on their canal systems - asconoid, syconoid and leuconoid.Īsconoid sponges have the simplest type of organization. The body wall is perforated by many pores and channels through which water enters the animal, passing into the spongocoel, and exiting it through a large opening, the osculum (4.1 in text). The simplest body wall is approximately two cell layers thick with a gel like substance called the mesenchyme or mesohyl in-between. The general body plan consists of "more or less" recognizable cell types surrounding a spongocoel. The 9,000 or so species are all aquatic with most representatives living in salt water, although about 100 species live in fresh water habitats. T he Latin name of the phylum derives from the numerous pores found on the body surface. Īll adults sessile and attached to substratum.Īsexual reproduction by buds and gemmules and sexual reproduction by eggs and sperm free-swimming ciliated larvae. No organs or true tissues digestion intracellular, excretion and respiration by diffusion. Skeletal structure of collagen and calcareous or siliceous spicules.
Įpidermis of flat pinacocytes interior surfaces lined with choanocytes that create water currents area between a gelatinous protein matrix called mesoglea. Multicellular, body traditionally considered a loose aggregation of cells.īody with pores, canals and chambers that serve for passage of water.
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