Brown vulcano carpet sponge
(Duchassaing & Michelotti, 1864)
This sponge grows in two distinct habits: 1) Massive-amorphous, irregularly lobate forms, with contorted, conical projections, which may or may not have apical oscules; 2) Incrusting forms, 2-3 mm thick, covering large areas, up to 1 square meter or more. The surface is smooth, velvety, especially on projections, otherwise commonly coarsely verrucose, with simple or compound bumps 2-10 mm in diameter and 1-2 mm high. The oscules of the massive form are provided with conical collars, or situated on top of chimneys. Their diameter is 0.5-2.5 cm. Those of incrusting forms are more regularly disturbed, with collars 2-5 mm high. The consistency is firm, somewhat rubbery.
The color of massive forms is tan to brown, paler around the base and oscules. Incrusting forms are frequently darker, greenish, or a mixture of brown and green.
Incrusting forms bore into solid substrates of deeper reefs by secreting minute amounts of acid. The massive forms inhabit shallow fringing and patch reefs, areas of coral rubble and grass flats.
Florida, Bahamas and Caribbean.