CONTENTS 



No. 1. AUGUST 



LiBBiE H. Lyman and Albert E. Galigher. Direct demonstration of the 

 existence of a metabolic gradient in annelids. Three figures 1 



Chikanosuke Ogawa. Experiments on the orientation of the ear vesicle in 



amphibian larvae. Twenty-four figures 17 



Edward C. Day. The physiology of the nervous system of the tunicate. II. 



The relation of the nerve ganglion to the heart 45 



M. E. CoLLETT. The toxicity of acids to Infusoria. II. The role of molecule 



and of ions 67 



M. E. CoLLETT. The toxicity of acids to Infusoria. III. Antagonism of 



the toxic action of acids by inorganic chlorides. Two figures 75 



Raymond Pearl and William Freeman Schoppe. Studies on the physi- 

 ology of reproduction in the domestic fowl. XVIII. Further obser- 

 vations on the anatomical basis of fecundity. Two figures 101 



No. 2. OCTOBER 



W. W. Swingle. The relation of the pars intermedia of the hypophysis to 

 pigmentation changes in anuran larvae. Four text figures and two 

 plates 119 



Joseph Hall Bodine. Some factors influencing the catalase content of 

 organisms. Three figures 143 



S. O. Mast. Reactions to light in the larvae of the ascidians, Amaroucium 

 constellatum and Amaroucium pellucidum, with special reference to 

 photic orientation. Ten figures 149 



A. C. Walton. The spermatogenesis of Ascaris felis Goeze. Two plates 

 (twelve figures) 189 



Charles Zeleny. The direction and frequency of mutation in the bar-eye 

 series of multiple allelomorphs of Drosophila. Five figures 203 



Vasil Obreshkove. The photic reactions of tadpoles in relation to the 

 Bunsen-Roscoe law. Nine figures 235 



No. 3 NOVEMBER 



Theophiltjs S. Painter. Studies in reptilian spermatogenesis. I. The 

 spermatogenesis of lizards. Six text figures and four plates (forty- 

 eight figures) 281 



I feTa7 



