This sponge occurs in two distinct habits, which are also separated by color and habitat.
Type (a) is amorphous, with globular lobes, or thickly incrusting, up to about 1 cm thick, spreading horizontally, with pronounced, deeply incised and lacunose, meandering lobes. This type never covers large areas. The oscules are inconspicuous, few, 0.5-1.5 mm in diameter, flush. The surface is smooth, glabrous, shiny. The consistency is soft, elastic, tough; reminiscent of fresh liver.
Type (b) is thinly incrusting on rocky substrates, 1-2 mm thick, with incised margins and lacunae, but cover larger, more continuous areas than type (a). The oscules are conspicuous, more numerous than in type (a), up to 3 mm wide and usually slightly elevated. The surface is smooth, glabrous, shiny. The consistency is somewhat tougher and more cartilaginous than in type (a).
The upper surface of type (a) is dark-brown to walnut-brown or beige; often mottled. The base and inner tissue are light beige to buff. Specimens growing in dark areas may be pale.
The color of type (b) is commonly yellowish-brown, fulvous, with dark brown rims and oscules surrounded by paler areas.
Specimens of type (a) are among the most common sponges in lagoons, where the lobes are attached to the vegetation or the incrustations spreading over rocky substrates or other sponges.
Specimens of type (b) seem to be restricted to the Millepora terraces and vertical cliffs.
From South Florida to the Caribbean.