The outer pinacoderm, the middle mesohyl, and the inner choanoderm.. The meaning of sponge is an elastic porous mass of interlacing horny fibers that forms the internal skeleton of various marine animals (phylum porifera) and is able when wetted to absorb.
Sponges are ancient animals that may appear simplistic, but the more we study them, the more we realize how complex they are.. Sponges are animals with dense skeletons that are highly adapted to their environments, although it is easy to see why they may be mistaken for plants.