THE PHYLA COELENTERATA AND CTENOPHORA 203 



4. How does a nematocyst work? 



5. Describe the role of diffusion in the physiology of coelenterates. 



6. What is a strobila? 



7. Distinguish between medusae and comb jellies. 



8. What is "regulation of form"? 



Supplementary Reading 



The Invertebrates, volume I, by L. Hyman includes both the radiate phyla, with 

 numerous drawings and an abundance of information. The photographs for these phyla 

 in Animals without Backbones by Buchsbaum are especially good. 



