1. Phylum Porifera

2. Phylum Porifera Sponges are the simplest animals Radially symmetrical
Acoelomate
Body resembles a perforated sac.
Has inner cavity called spongocoel
Has large opening called osculum
Lining body are cells flagellated cells called choanocytes
These cells beat to produce a flow of H20 into the sponge through pores in through the body wall, and out through the osculum.
Body wall is composed of many elements
Mesohyl - gelatenous material
Amoebocytes
Motile cells which perform many functions
Capture, digest and transport food
Create tough structural fibers of the body wall called spicules.

3. A Typical Sponge

4. Sponges