The Quarterly Review of BiologJ 



MARCH - JUNE - SEPTEMBER - DECEMBER 

 RAYMOND PEARL, Editor 



Institute for Biological Research 

 The Johns Hopkins University 



ASSISTED BY 



R. W. Hegner Blanche F. Pooler John Rice Miner 



Contributing Editor Assistant Editor Assistant Editor 



The Johns Hopkins University 



Advisory Board 



ANATOMY Lewis H. Weed The Johns Hopkins University. 



ANTHROPOLOGY A. L. Kroeber University of California 



BEHAVIOR AND COMPARA- 

 TIVE PSYCHOLOGY K. S. Lashley University of Minnesota: 



BOTANY Irving W. Bailey Harvard University 



CYTOLOGY Edmund B. Wilson Columbia University 1 . 



ECOLOGY William Morton Wheeler Harvard University'- 



EMBRYOLOGY E. G. Conklin Princeton University 



EXPERIMENTAL MOR- 

 PHOLOGY Ross G. Harrison Yale University, 



GENERAL PHYSIOLOGY. . . . J Lawre nce J. Henderson 



IG. H. Parker Harvard University 



GENETICS P^' ^" Emerson Cornell University. 



' 'IT. H. Morgan Columbia University 



GEOGRAPHICAL DISTRIBU- 

 TION AND TAXONOMY Alex. G. Ruthven University of Michigan 



PALEONTOLOGY John C. Merriam Carnegie Institution 



ZOOLOGY Frank R. Lillie University of Chicago', 



Interesting Papers to Appear in Early Numbers 



Animal Evolution. Austin H. Clark, Smithsonian Institution. 



Life Zones. E. W. Nelson, Bureau of Biological Survey, U. S. Department of Agriculture. 



The Cytology of Glandular Secretions. R. H. Bowen, Columbia University. 



Facial Expression. Ernst Huber, Johns Hopkins University. 



The Metabolism of Insects. Mary H. Sayle, University of Wisconsin. 



The Problem of Senescence and Rejuvenescence in the Protozoa. L. L. Woodruff, ; 



Yale University. 

 The Chloroplast Pigments. Frank M. Schertz, Washington, D. C. 

 Social Parasitism in Birds. Herbert Friedmann, Amherst College. 

 Natural Hybrid Trees. John G. Jack, Arnold Arboretum. 



Copyright 1928, The Williams & Wilkins Company. 



Entered as second-class matter January 27, 1926, at the post office at Baltimore, Maryland, under the Act of March 3, 1876. 



$5.00 a year ($5.50 outside Postal Union) $1.50 a copy. 



Made in United States of America 



