x PREFACE 



Kingsley, J. S. The Vertebrate Skeleton. London. 



1925. 



Lull, R. S. Organic Evolution. New York. 1917. 



von Zittel, K. A. Grundziige der Palaontologie. Vol. II. 

 Berlin. 191 8. 



With regard to the figures, I have preferred to illustrate a 

 few points thoroughly, rather than attempt to provide a picture 

 of all the structures that are worthy of attention. In any case, 

 a picture is but a poor substitute for the structure itself. The 

 majority of the figures were drawn specially for this book from 

 dissections and laboratory preparations, and my intention has 

 been to show that the student should have no difficulty in 

 examining for himself the structures here figured (and many 

 more besides which are not figured in this book), in any fairly- 

 well equipped laboratory. I am indebted to my wife for pre- 

 paring the figures for press, and to the following authors and 

 publishers for permission to reproduce figures : to the Dele- 

 gates of the Clarendon Press for figs. 73, 74, 75, 88, 89, 92, 94, 

 95, 96, 101, 102, 109, no, 114, 115, 116, from J. W. Jenkinson's 

 Vertebrate Embryology, and for permission to copy figs. 87, 

 90, 91, 93, 97, 98, 108, 113, from the same work ; to Professor 

 G. Elliot Smith and Mr. Humphrey Milford for figs. 180, 181, 

 183, from Essays on the Evolution of Man ; to Professor Boule 

 for fig. 182 ; to the Editor of the Quarterly Journal of Micro- 

 scopical Science for permission to copy fig. 118 ; to Professor 

 W. K. Gregory and the American Museum of Natural History 

 for permission to copy part of fig. 158 ; to Professor L. Bolk 

 for permission to copy fig. 123 ; to Professor W. J. Sollas for 

 permission to copy fig. 182 ; and to Mr. B. W. Tucker and 

 Mr. J. Z. Young for the loan of drawings of dissections. 



In conclusion, I wish to express to Messrs. Sidgwick and 

 Jackson my appreciation of the care and skill which they have 

 so kindly shown in the preparation of this book. 



G. R. de B. 



Oxford, 

 February, 1928. 



