Phillip V. Tobias is Professor of Anatomy at the University 

 of the Witwatersrand, Johannesburg. 



This book is based on the author's James Arthur Lecture, 

 delivered at the American Museum of Natural History, 

 New York City, April 30, 1969; it was the thirty-eighth in 

 this series of lectures. 



Copyright © 1971 Columbia University Press 

 International Standard Book Number: 0-231-03518-7 

 Library of Congress Catalog Card Number: 78-158458 

 Printed in the United States of America 



LIBRARY 



OFTHE 



AMERICAN MUSEUM 



