Sponges are generally considered to be among the most primitive of animals. They have no organs, but are rather and assemblage of several kinds of specialized cells. A sponge feeds by moving water in through small pores on its surface into chambers where plankton is trapped by specialized collar cells. The water is then pumped into larger chambers and expelled through large pores. Both of the common sponges in Bartlett Cove are encrusting forms, which means that they spread over the surfaces of rocks in a relatively thin layer. The bread crumb sponge (Halichondria) is greenish color, up to an inch thick and has a very distinctive odor. The other common sponge, Haliclona, is thinner and smoother, with conspicuous volcano-like pores and a deep shade or purple or pink.
Last updated: March 16, 2018