258 



QUESTIONS ON THE CCELENTERATA. 



12. Compare the structure of the tentacles in 



a. Physalia; 



b. Forskalia; 



c. Apoleraia. 



13. What is the position of the tentacles in the following genera of 



Hydrozoa : 



a. Tubularia; 



b. Hvdractinia; 



c. Diphyes ; 



d. Porpita; 



e. Pelagia? 



14. Describe the ' pneumatocyst ' of any of the Physophoridse, and 



the principal modifications which it presents among other 

 genera of the same order. 



15. Describe, as to structure and position, 



a. the marginal ' vesicle ' of Geryonia ; 



b. the * lithocyst ' of a free Lucernarid. 



16. How are the 'gonophores' situated in the following genera of 



Corynidaj : 



a. Tubularia; 



b. Hvdractinia: 



c. Clavatella; 



d. Cordylophora? 



17. Compare the structural relations of the reproductive organs in 



a. Lucernaria; 



b. Aurelia; 



c. Rhizostoma. 



18. What are * gonoblastidia ' ? Explain the modifications which 



these structures present among the Sertularidse. 



19. In what genera of Lucernaridas do free reproductive zooids 



occur ? Trace the development of any of these forms. 



20. Describe the development of a medusiform gonophore. 



21. Give some account of the early stages of development in 



a. Cordylophora lacustris ; 



b. Campanularia Loveni ; 



c. Cunina octonaria. 



22. What rule seems to govern the successive development of the 



appendages among the Plrysophorida} ? 



23. Define- the orders: 



a. SertularidiB ; 



b. Calycophoridaa ; 



c. Lucernaridie. 



