Sea Squirt and Sponge Cross-Sections

I saw some sea squirts while in Dahab, which were pretty amazing. They're, to the untrained eye, somewhat like upside down jellyfish minus the tentacles and attached to the reef. I found a cluster of three rarely seen sand dwelling anemones too but that's another story. These diagrams are, as are all the black and white illustrations like these, for the D.E.A.R. textbook. They'll be labelled and annotated by someone who knows what they're talking about.

'Sea Squirt and Sponge Cross-sections' - 2009