It is an encrusting sponge, with an ascon-type single-bag structure, which forms lemon-yellow bearings, up to 10 cm in diameter, composed of tubules with a diameter of 0.5 to 1 mm, twisted into a lattice; the consistency is soft because the limestone component is limited to the spicules, which are triassones with cylindrical-conical spokes.
It is an encrusting sponge with leucon type morphology. From life to colonies with a translucent appearance of fleshy consistency, of a light blue to blue-gray color, 1-3 mm thick and wide up to 15-20 cm2. Inhalant orifices are grouped together and the osculae are in a high position. The exhilarating channels are visible in transparency.
It has a globular shape and a cartilaginous consistency, with a smooth and shiny surface. The color varies from smoky gray to different shades of brown. In unlit environments it can also take on a whitish color. The color variations are due, as in other species of Demospongiae, to the symbiotic relationship with photosynthetic cyanobacteria, present in the surface tissues of the sponge in concentrations that vary according to the habitat lighting conditions.
From life to colonies of various shapes, sometimes to plates, sometimes with irregular confluent ramifications. The surface is rough to the touch. The oscules measure 3-5 mm in diameter and have a collar collar. The consistency is particularly compact. The color ranges from purple to brown in lighted areas, from pink to off-white in the shaded areas.
The red sponge or spirastrella is an encrusting sponge from the Spirastrellidae family. Red-orange in color, sometimes green, blue, gray. Characterized by very evident channels that culminate in the oscula, rough to the touch due to the presence of spicules. It can also cover large expanses of bottom. It can be confused with the encrusting forms of Crambe crambe.