User:Pooja srivastava/E-Museum/Porifera

=Characterstics of Porifera=


 * They are generally called sponges.
 * They are sessile,sedentary and marine.
 * Body is cylindrical ,asymmetrical or radial symmetry.
 * Sponge body consists of an outer layer ectoderm ,middle layer mesenchyme and an inner layer endoderm.
 * Body also contains numerous pores called ostia through which water enters in the body.
 * The internal body space is either hollow or contains numerous canals lined with choanocytes(fllagelated cells).
 * Body also contains one or more openings called oscula by which water passes out.
 * They feed on minute organisms and small organic particles ingested by choanocytes.
 * Respiration takes place by intake of oxygen from water current.
 * The skeletal system of soponges is made up of spongin fibers and calcareous spicules.

/Some common examples of Porifera/