264 THE BIOLOGY OF HYDRA : 1961 



symbiotic algae can account for this by promoting efficient utiliza- 

 tion of available food. 



ACKNOWLEDGEMENTS 



It is a pleasure to acknowledge the counsel of Drs. C. Hand and 

 R. I. Smith at the University of California, Berkeley. Studies on 

 hydra were initiated under the guidance of Dr. H. M. Lenhoff, to 

 whom I am indebted for help in all phases of this investigation. 



REFERENCES 



1. Brien, p. 1961. The fresh-water hydra. Amcr. Sci. 48: 461-475. 



2. Dixon, M. 1941. Multi-enzyme systems. Cambridge, 100 pp. 



3. GoREAU, T. F. and N. I. Goreau. 1960. Distribution of labeled carbon in rccf- 



building corals with and without zooxanthellae. Science 131: 668-669. 



4. Lenhoff, H. M. and J. Bovaird. 1961. A quantitative chemical approach to 



problems of nematocyst distribution and replacement in Hydra. Detyelop. 

 Biol. 3: 227-240. 



5. Lenhoff, H. M. and K. F. Zimmerman. 1959. Biochemical studies of symbiosis 



in Chlorohydra viridissima. Anat. Rec. 134: 559. 



6. LooMis, W. F. 1954. Environmental factors controlling growth in hydra. /. Exp. 



Zool. 126: 223-234. 



7. LooMis, W. F. and H. M. Lenhoff. 1956. Growth and sexual differentiation of 



hydra in mass culture. /. Exp. Zool. 132: 555-574. 



8. Muscatine, L. 1961. Some aspects of the relationship between a sea anemone 



and its symbiotic algae. Ph.D. Thesis, University of California, Berkeley, 

 100 pp. 



9. Muscatine, L. and C. Hand. 1958. Direct evidence for transfer of materials 



from symbiotic algae to the tissues of a coelcnterate. Proc. Nat. Acad. Sci. 

 44: 1259-1263. 



10. Odum, H. T. and E. P. Odum. 1955. Trophic structure and productivity of a 



windward coral reef community on Eniwetok atoll. Ecol. Monogr. 25: 

 291-320. 



11. Sargent, M. and T. S. Austin. 1949. Organic productivity of an atoll. Traits. 



Amer. Geophys. Union 30: 245-249. 



12. Sargent, M. and T. S. Austin. 1954. Biologic economy of coral reefs. U. S. 



Geol. Survey Prof. Pap. 260E, pp. 299-300. 



13. Whitney, D. D. 1907. Artificial removal of the green bodies of Hydra viridis. 



Biol. Bull. 13: 291-299. 



14. Wood, R. L. 1959. Intercellular attachment in the epithelium of Hydra as 



revealed by electron microscopy. /. Biophysic. Biochem. Cytol. 6: 343-352. 

 See also p. 55, this volume. 



