Mycale laevis

Mycale laevis is yellow, mid to dark orange or yellowish-green. It has a small number of oscules, each up to 4 millimetres (0.16 in) in diameter. They are elevated with a thick white or translucent collar. This sponge is easily torn and its consistency is compressible but firm.[2][3]

Mycale laevis usually grows on the undersurface of certain species of corals that form flat plates. These include Montastraea annularis, Montastraea cavernosa, Porites astreoides, Agaricia agaricites and Mycetophilia lamarckiana.[4] The sponge seems able to cause the rim of the coral to fold and become lobed and inserts its oscules in the gaps between the lobes. Often the sponge is found covering the under side of an entire groups of colonial corals. It is unclear what is the precise relationship between the coral and the sponge but the latter may benefit from being held clear of the substrate while the coral may avoid having its undersurface mined by a parasitic boring sponge. Observation over several years has shown that this is a stable relationship. In the absence of suitable coral species, Mycale laevis is able to live directly on rocks and under boulders as an encrusting or massive sponge[4] and also on calcareous worm tubes.[3]

Mycale laevis is found on reefs and in lagoons in the Caribbean Sea, the Gulf of Mexico, the West Indies, the Bahamas and Florida at depths between 1 and 80 metres (3.3 and 262.5 ft) but is more common at depths greater than 25 metres (82 ft).[4]