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QUESTIONS ON THE COELENTERATA 



i. By what structural features are Coelenterata separated from other 

 primary divisions of the animal kingdom ? 



2. Contrast the two sub-kingdoms, Protozoa and Coelenterata. 



3. Describe the typical structure of a thread-cell. 



4. Compare the classes, Hydrozoa and Actinozoa. 



5. Describe the structure of Hydra. How does the ' polypite ' of 



this genus differ from that of the non- budding forms of the 

 CorynidaB ? 



6. Define the terms, 



a. * hvdrotheca ' : 



b. ' hydrophyllium ' ; 



c. 'hydrocyst.' 



7. In what order of Hydrozoa do ' nematophores 9 occur? Describe 



the structure and position of these appendages. 



8. Describe the structure of a ' nectocalyx.' How does this organ 



differ from an ' umbrella ' ? 



9. Describe the structure and relations of the nectocalyces in 



Diphyes, and state how the same parts are modified in 

 Praya. 



10. In what Physophorida? are nectocalyces absent? 



11. Briefly describe the modifications of the ccenosarc, and relative 



attachment of its appendages, in the following genera of 



Physophoridse : 



a. Physophora; 



b. Stephanomia; 



c. Apolemia; 



d. Athorybia; 



e. Velella. 



S 



