Asconoid is one of three possible body plans for sponges, which form the phylum Porifera in kingdom Animalia. The asconoid body plan is characterized by a stalk-like spongocoel surrounded by a single layer of choanocytes. These choanocytes are cells that have flagella, and the flagella beat to push water through the spongocoel, creating a current. At somewhat regular intervals along the lining of the spongocoel are openings called ostiums. These protrude through the outer layer of the sponge (somewhat like an epidermis, but not entirely like it, since this terminology implies germ layers, which sponges do not have. Finally, at the top of the sponge is the osculum, which is the final exit for water circulating through the sponge. This article is about the animal. ... Phylum (plural: phyla) is a taxon used in the classification of life, adopted from the Greek phylai the clan-based voting groups in Greek city-states. ... The sponge, in the phylum Porifera, is a very primitive and specialized animal. ... Phyla Subkingdom Parazoa Porifera (sponges) Subkingdom Agnotozoa Placozoa Orthonectida Rhombozoa Subkingdom Metazoa Radiata Cnidaria Ctenophora - Comb jellies Bilateria Protostomia Acoelomorpha Platyhelminthes - Flatworms Nemertina - Ribbon worms Gastrotricha Gnathostomulida - Jawed worms Micrognathozoa Rotifera - Rotifers Acanthocephala Priapulida Kinorhyncha Loricifera Entoprocta Nematoda - Roundworms Nematomorpha - Horsehair worms Cycliophora Mollusca - Mollusks Sipuncula - Peanut worms Annelida - Segmented... Category: Cell biology stubs ... A flagellum (plural, flagella) is a whip-like organelle that many unicellular organisms, and some multicellular ones, use to move about. ... A current is the rate of fluid flow, especially water or air. ... Epidermis could refer to: In plants, the outermost layer of cells covering the leaves and young parts of a plant is the epidermis. ... It has been suggested that endoderm be merged into this article or section. ...