CONTENTS OF VOLUME XXXIX. 



No. i. JULY, 1920 



Twenty-Second Annual Report of the Marine Biological Labor- 

 atory for the Year 1920 i 



COE, WESLEY R. Sexual Dimorphism in Nemerteans 36 



BALDWIN, W. M. A Study of the Combined Action of X-rays 



of Vital Stains upon Paramozcia 59 



ANDREWS, E. A. Alternate Phases in Folliculina 67 



No. 2. AUGUST, 1920 



DODDS, GIDEON S. Entomostraca and Life Zones 89 



CROZIER, W. J. Notes on Some Problems of Adaptation, I . . 108 

 CROZIER, W. J. Notes on Some Problems of Adaptation, II .. 1 16 

 CROZIER, W. J. Notes on Some Problems of Adaptation, III . 130 

 GLASER, R. W. Biological Studies on Intracellular Bacteria, 



No. i 133 



No. 3. SEPTEMBER, 1920 



CHILD, C. M. Some Consideration Concerning the Nature 



and Origin of Physiological Gradients 147 



COWT>RY, N. H. Experimental Studies on Mitochondria in 



Plant Cells 188 



No. 4. OCTOBER, 1920 



NONIDEZ, JOSE F. The Internal Phenomena of Reproduction 



in Drosophila 207 



MORGAN, T. H. The Effects of Castration of Hen-Feathered 



Campines 231 



MORGAN, T. H. The Effects of Ligating the Tests of Hen- 

 Feathered Cocks 248 



MORGAN, T. H. The Genetic Factor for Hen- Feathering in 



the Sebright Bantam 257 



iii 



