Plate XVI. 



Diagrams descriptive of structure of Polyzoa. 



rt '^^i-'^" 1. Diagram of Polyzoa (after Busk). 

 )'yvj^^,<^.,..-<^^ 2. Diagram of Bowerbankia (after Hincks). 



3. Polyzoon with polypide retracted (after Hincks). 



4, 5. Communication plates (after Hincks). 



6. Alimentary canal of Cellepora (after Hincks). 



7. " Bird's Head " processes, p. 208. 



8. Structure of Notamia bursaria (after Busk). 



For descriptions of these figures, see chapter on 

 Structure of Polyzoa, pp. 201—210. 



