PREFACE vii 



reference is included in the list at the end of the chapter in which 

 the figure appears. 



For permission to cite unpublished data I am indebted to 

 Dr. S. Tashiro, of the Department of Biochemistry, to Miss L. H. 

 Hyman, of the Department of Zoology, and to Mr. M. M. Wells, 

 formerly of the Department of Zoology, of the University of Chicago. 

 For the redrawing of all figures from other authors and for a num- 

 ber of original drawings from preparations I am indebted to Mr. 

 Kenji Toda, the artist of the Department of Zoology, and I wish to 

 express my appreciation of his work. For the reading of parts of 

 the manuscript and proofs and for various suggestions and criti- 

 cisms my thanks are due to my colleagues, Dr. A. P. Mathews 

 and Dr. C. J. Herrick. To my wife, Lydia Van Meter Child, I 

 am deeply indebted for her unfailing co-operation and assistance 

 in the preparation of the manuscript and proofs. And, lastly, I 

 wish to express my appreciation of the manner in which the Uni- 

 versity of Chicago Press has done its part as publisher. 



C. M. CHILD 



HULL ZOOLOGICAL LABORATORY 



UNIVERSITY OF CHICAGO 



May, 1915 



