ClipArt ETC
"Diagram showing types of canal system. --After Korschelt and Heider. The flagellate regions are dark throughout, the mesogloea is dotted, the arrows show the direction of the currents. All the figures represent cross-sections through the wall. A. Simple Ascon type (Ec., outer layer; En., inner layer; Mg., mesogloea). B. Sycon type, with flagellage radial chambers (r.c.). CC. Leucon type, with flagellate side aisles on the main radial chambers. D. Still more complex type, with small flagellate chambers (f.ch.)." -Thomson, 1916

Sponge Canal System

"Diagram showing types of canal system. --After Korschelt and Heider. The flagellate regions are dark…