CONTENTS 



NO. 1 JANUARY 



H. O. Mast. The process of orientation in the colonial organism, Gonium pectorale, 



and a study of the structure and function of the eyespot. Six figures 1 



K. S. Lashlby. Results of continued selection in Hydra 19 



NO. 2 FEBRUARY 



Harold Saxton Burr. The effects of the removal of the nasal pits in Amblystoma em- 

 bryos. Fourteen figures (three plates) 27 



Rhoda Erdmann and Lorande Loss Woodruff. The periodic reorganization process 



in Paramaecium caudatum. Thirty-five figures (seven plates) 59 



LiBBiE H. Hyman. An analysis of the process of regeneration in certain microdrilous 



oligochaetes. Twenty-four figures 99 



S. R. Detwiler. The effect of light on the retina of the tortoise and of the lizard. 



Eleven figures 165 



Reynold A. Spaeth. Evidenc^e proving the melanuphore to be a disguised type of 



smooth muscle cell. Two figures 193 



Jacques Loeb and Hardolph Wasteneys. The relative efficiency of various jmrts of 



the spectrum for the hcliotropic reactions of animals and i)lants. Six figures 217 



Henry Laurens. The reactions of the melanophores of Amblystoma larvae — the sup- 

 posed influence of the pineal organ. Six figures 237 



David Day Whitney. The control of sex by food in five species of rotifers. Six figures 263 



NO. 3 APRIL 



W. J. Crozier. The rhythmic pulsation of the cloaca of Ilolothurians. Thirty-one 



figures 297 



William L. Dolley, Jr. Reactions to light in Vanessa antiopa, with special reference 



to circus movements. Twenty-one figures 357 



H. D. Goodale. A feminized cockerel. Seven, figures 421 



Selig Hecht. The water current produced by Ascidia atra Lesueur. One figure 429 



E. A. Andrews. Color changes in the rhinoceros beetle, Dynestes tityrus. Four 



figures 435 



iii 



