organic debris. It has been calculated that a sponge can filter of water per day. The sponge is a hermaphrodite. After fertilisation, the embryos are brooded inside the sponge, and when they reach the last embryonic stage, they pass out through the oscula into the water column. They drift with the plankton, and after a few hours, settle on the seabed, attach themselves to the substrate and become juvenile sponges. The sponge can also reproduce asexually by budding, and like all sponges, it has great powers of regeneration. References Halichondrida Fauna of the Atlantic Ocean Fauna of the Mediterranean Sea Animals described in 1935