The crumb-of-bread sponge, Hymeniacidon perlevis, is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of sponge in the class

Class (biology)

In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...

 demosponges.

Distribution

The crumb-of-bread sponge is found in the northern Atlantic Ocean, the Mediterranean sea and the Pacific Ocean, as well as around the southern African coast from the northern Cape to Port St Johns. It lives from the intertidal to 15m underwater.

Description

It is a thickly encrusting sponge with a glistening bumpy surface. Specimens found intertidally are bright yellow. Specimens from deeper water are darker. The oscula

Osculum

The osculum is an excretory structure in the living sponge, a large opening to the outside through which the current of water exits after passing through the spongocoel. Wastes diffuse into the water and the water exits through the osculum at a velocity of nearly 8.4 cm/second, carrying away with...

are scattered across the surface of the sponge and may be flush with the sponge surface or on raised mounds.

Ecology

The form of the sponge is variable, depending on its environment. In sheltered areas, branched structures grow from the base. In areas with wave action the surface is convoluted or flat.