230 FROM FISH TO PHILOSOPHER 



2.2.. Jepsen, G. L., E. Mayr, and G. G. Simpson. Genet- 

 ics, ? (deontology, and Evolution. Princeton Univer- 

 sity Press, Princeton, N. J., 1949. 



23. ScHEiNFELD, A. The "New You and Heredity. J. B. 

 Lippincott Co., Philadelphia and New York, 1950. 



24. Simpson, G. G. The problem of plan and purpose 

 in nature. Scientific Monthly, 64: 481. 1947. 



25. Simpson, G. G. The Meaning of Evolution. Yale 

 University Press, New Haven, Conn., 1949. 



The calculation of chromosomal and genie permuta- 

 tions is that of T. Dobzhansky, cited by Scheinfeld {23}, 

 whose popular book is recommended to anyone inter- 

 ested in human genetics. 



I have drawn heavily on many of G. G. Simpson's 

 works; the 'alphabet' is cited from {24}, and quotations 

 are drawn from this article and from {25}. 



The issues of 'directed' evolution, vitahsm versus ma- 

 terialism, and related topics, are discussed by Jepsen 

 {21}; by Colbert, in 'Progressive adaptations as seen in 

 the fossil record' in {22}; by Wright in 'Adaptation and 

 selection' in {22}, and by Simpson {24, 25}. 



III. THE PROTOVERTEBRATE 



26. Barrell, J. Dominantly fluviatile origin under sea- 

 sonal rainfall of the Old Red Sandstone. Bulletin of 

 the Geological Society of America, 27: 345. 1916. 



27. Barrell, J. The influence of Silurian-Devonian cU- 

 mates on the rise of air-breathing vertebrates. Bul- 

 letin of the Geological Society of America, 27: 387. 

 1916. 



28. Berrill, N. J. The Origin of Vertebrates. Clarendon 

 Press, Oxford, 1955. 



29. Bryant, W. L. A study of the oldest knov/n verte- 

 brates, Astraspis and Eriptychius. Proceedings of the 

 American Philosophical Society, 76: 409. 1936. 



