282 THE BIOLOGY OF HYDRA : 1961 



14. Teichert, C. 1958. Cold and deep water coral banks. Am. Assoc. Petr. Gcol. 



Bull. 42: 1064. 



15. Thiel, M. E. 1929. Zur Fra,^e der Ernahning der Steinkorallen und der Bredeu- 



tung Ihrer Zooxanthellen. Zoo/. Anz. 81: 295. 



16. Tracey, J. I., H. S. Lauu and J. E. Hokfmeister. 1948. Reefs of Bikini, Mar- 



shall Islands. Geol. Soc Am. Bull. 59: 861-878. 



17. Vaughan, T. W. and J. W. Wells. 1943. Revision of the suborders, families 



and genera of the Scleractinia. Geol. Soc. Amer. Spec. Pap. 44: 363 pp. 



18. Vinogradov, A. P. 1953. The elementary chemical composition of marine 



organisms. Sears Found. Mar. Res. Mem. II: 647 pp. 



19. Yonge, C. M. 1940. The biology of reef building corals. Gt. Barrier Reef Expecl. 



Set. Rep. 7(13): 353-391.' 



20. Yonge, C. M. 1957. Symbiosis. Geol. Soc. Amer. Mem. 67 (l): 429-442. 



21. Yonge, C. M. and A. G. Nicholls. 1931. Studies on the Physiology of corals. 



V. The effect of starvation in light and darkness on the relationship 

 between corals and zooxanthellae. Gt. Barrier Reef Expecl. Sci. Rep. 

 1(7): 177-211. 



DISCUSSION 



WAINWRIGHT: First I'd like to wave a small flag because you 

 who have trays of hydra in your laboratory and even you ocean- 

 ographers with laboratories in a ship don't have any idea under 

 what difficulties Dr. Goreau is working and what he has done in 

 taking his laboratory down onto the reef. Think of diving to 100 feet 

 with 200 pounds of machinery on your back and then doing a critical 

 experiment using glassware, radioisotopes, and lixing animals. 



Now I want to ask a question. Do you know what the limiting 

 factors in calcification are? 



GOREAU: No, not yet, if we exclude light for the moment. Con- 

 trary to what I said earlier, it may be possible to culture some species 

 of corals in vitro. We must never assume, however, that the growth 

 or accretion rates we measure under those conditions are equal to 

 those occurring on the reef. Nevertheless, laboratory studies are use- 

 ful because we can rigidly control the environment, the concentra- 

 tion of such substances as HCO^ and Ca++ and the additions of 

 inhibitors or stimulants, etc. We are planning such studies, but 

 haven't gotten around to them yet, so I cannot really answer your 

 question. 



MUSCATINE: Do you feel that calcification in corals is augment- 

 ed by removal of COo by zooxanthellae? 



