The asconoïde is one of the three body forms possible at the sponge S (Phylum Porifera). The asconoïde plan is characterized by animals without definite body form. Only one layer of Choanocyte S papers the Spongocoele, in which the Eau penetrates directly by the ostia. This type of plan is found only at small sponges, because it is not very effective; indeed, the surface available covered of choanocytes cannot satisfy the metabolic needs (nutrition, gaseous exchange and excretion) for a great volume of cells.