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.