THIS BOOK IS AFFECTIONATELY DEDICATED TO 



DR. J. A. ALLEN 



WHO, THROUGH HIS PROFOUND KNOWLEDGE, UNSELFISH 

 DEVOTION TO SCIENCE, AND NEVER-FAILING SYMPATHY 

 WITH YOUNGER STUDENTS OF ZOOLOGY HAS 

 BEEN AN EXAMPLE AND AN INSPIRATION DURING 

 THE YEABS I HAVE WORKED AT HIS SIDE. 



442-547 



