 As many as 16,000 individuals inhabit a single loggerhead sponge, feeding off the larger particles that collect on the sponge as it filters the ocean to feed itself.Linnaeus, who classified most kinds of sessile animals as belonging to the order Zoophyta in the class Vermes, mistakenly identified the genus "Spongia" as plants in the order Algae.For a long time thereafter sponges were assigned to a separate subkingdom, Parazoa ("beside the animals"), separate from the Eumetazoa which formed the rest of the kingdom Animalia.