Published, 1956, by Princeton University Press 

 London: Geoffrey Cumberlege, Oxford University Press 



ALL RIGHTS RESERVED 



No part of this book may be reproduced in any form 

 without permission of the author 



Device on title page, Aristotle's Lantern, from a wood- 

 cut by Edward Forbes, A History of British Star- 

 fishes, and other Animals of the Class Echinodermata 

 (London, 1841). 



Composition by N.V. Drukkerij G. J. Thieme, Nijmegen, The Netherlands 

 Printed in the United States of America 



