THE BIOLOGIST POSES SOME PROBLEMS 93 



salinity. From such localities the true ocean may have received 

 its biota in the earlier stages of its development. This is indeed 

 the simplest hypothesis that we can put forward on purely bio- 

 logical grounds. It may prove to be a hypothesis of low survival 

 value. Something like it was suggested by Chamberlin (e.g., 

 Chamberlin and Salisbury, 1904, p. 627) over fifty years ago, and 

 again by Macfarlane (1923). To the majority of you, as oceanogra- 

 phers, it may seem merely the warped production of the brain of 

 a limnologist. Time and the other papers in this volume may well 

 show that I am wrong. 



[Note added in proof. Since the above lecture was delivered, I have learnt 

 that the hypothesis of predation as the stimulus to the production of hard 

 fossilizable skeletons had already been put forward by Dr. Harold K. 

 Brooks in a paper that has apparently not yet appeared. — G. E. H. 

 28 June, I960.] 



REFERENCES 



Chamberlin, T. C, and R. D. Salisbury. 1904. Geology. (American 



Science Series — Advanced Course). Vol. I. Geologic Processes and 



Their Results. Henry Holt, New York. 

 Cloud, P. E. 1948. Some problems and patterns of evolution exemplified 



by fossil invertebrates. Evolution, 2, 322-350. 

 Conway, E. J. 1942. Mean geochemical data in relation to oceanic 



evolution. Proc. Roy. Irish Acad., B48, 119-159. 

 . 1943. The chemical evolution of the ocean. Proc. Roy. Irish 



Acad., B48, 161-212 

 Dougherty, E. C, and M. B Allen. 1959. Speculations on the position 



of the cryptomonads in protistan phylogeny. XV Intern. Congr. 



Zool., London 1958, Proc. 184-186. 

 Hartman, O. 1938. Brackish and fresh-water Nereidae from the north- 

 east Pacific, with the description of a new species from Central 



California. Univ. Calif. Pubis. Zool., 43, 79-82. 

 Laidlaw, Sir P P., and W. J. Elford. 1936. A new group of filterable 



organisms. Proc. Roy. Soc. {London), B120, 292-303. 

 Macallum, A. B., 1926. The paleochemistry of the body fluids and 



tissues. Physiol. Revs. 6, 316-357. 

 Macfarlane, J. M. 1923. The Evolution and Distribution of Fishes. The 



Macmillan Company, New York. 

 Pantin, C. F. A. 1931. The origin of the composition of the body fluids 



in animals. Biol. Revs., 6, 459-482. 

 Pratt, D. B., and G. Waddell. 1959. Adaptation of marine bacteria to 



growth in media lacking sodium chloride. Nature, 183, 1208-1209. 



