vi PREFACE 



biological rhythms, both in plants and animals. The final portion of 

 the book presents research in the various phyla of animals on the 

 interrelation of light and temperature with periodic function, par- 

 ticularly with reference to mating behavior and reproduction. 



A great deal of appreciation is expressed to all the participants of 

 the symposium who have given wonderful assistance in the editing of 

 the book. The prompt and efficient cooperation of the authors in the 

 reading and return of their proof and the patient and painstaking 

 assistance of Webster True and Mrs. Vivienne Mitchell in the indexing 

 are gratefully acknowledged. 



Alice P. Withrow 



