Encrusting Red Sponge

0.5 to 3 cm thick. Smooth surface with diagnostic pattern of round, slightly elevated pore fields not greater than 0.5 cm wide. Exterior and interior dark red to red-brown. Fragile and soft. Dark exudate when damaged. Elevated round oscules distributed irregulary with thin transparent or colored marginal membrane. Abundant spicules support the rounded warts at the surface. Members of the class Demospongiae are hermaphroditic. Life cycle: The zygote develops into parenchymella larva (free-swimming) before settling down on a substrate where it grows into a young sponge.