CONTENTS 



The Chloroplast Pigments, Their Func- 

 tions, and the Probable Relation of 

 Chlorophyll to the Vitamines 



— F. M. Schertz (459-485) 



The Development of Modern Compar- 

 ative Psychology 



— C. J. Warden (486-522) 



Animal Evolution 



—Austin H. Clark (523-541) 



The Metabolism of Insects 



— Mary Honora Sayle (542-553) 



Social Parasitism in Birds 



—Herbert Friedmann (554-569) 



New Biological Books 

 Brief Notices (570-599) 



The Cost of Biological Books in 1928 



—Raymond Pearl (600-603) 



Index (605-611) 



