Habitat: Shallow water. In patchs reef and coraline habitat; usually in low branching corals. Distribution: Caribbean. Characteristics: Shape: thick encrusting, amorphous, size 6x3x1 cm (length, width, thickness) Color: pale green external and internally. Consistency: hard, not compressible. Surface: optically smooth, rough-rugose like sand paper when touched. Very porous under the microscope. Conules can be seen on the ectoderm 300-400 microns apart and 150-200 microns high Apertures: 2 mm diameter oscules randomly distributed. Skeleton: spicules: oxeas (200-10 microns). cavernous choanoderm. Uniform mesh size spicule reticulation. Paucispicular spicule tracts. Mesh size: 500 microns. Notes: Could be confused with Amphimedon viridis but 3 characteristics distinguish them: A. erina has 1. stiffer consistency, 2. ramose habit and 3. thicker spicules. Spicules in A.viridis are 153 x 6,8 microns.