CONTENTS 



No. 1 JANUARY 



E. J. Lund. The relations of Bursaria to food. I. Selection in feeding and 

 in extrusion. Eight figures 1 



*^ Alice M. Boring and Raymond Pearl. The odd chromosome in the sperma- 

 togenesis of the domestic chicken. Six plates 53 



Charles Packard. The effect of radium radiations on the fertilization of 

 Nereis 85 



John C. Phillips. A further studj' of size inheritance in ducks, with observa- 

 ' tions on the sex ratio of hybrid birds. Seven charts 131 



George L. Streeter. Experimental evidence concerning the determination 

 of posture of the membranous labyrinth in amphibian embryos. Thirt j^- 

 six figures 149 



No. 2 FEBRUARY 



E. C. MacDowell. Multiple factors in Mendelian inheritance 177 



/ Henry Laurens. The reactions of normal and eyeless amphibian larvae to 



light. Two figures 195 



George xVlfred Baitsell. Experiments on the reproduction of the hypo- 

 trichous Infusoria. II. A study of the so-called life cycle in Oxyt'ficha " 

 Jallax and Pleurotricha lanceolata. Sixteen figures (one plate) 211 



Lorande Loss Woodruff. On so-called conjugating and non-conjugating 



races of Paramaecium. One figure 237 



Arthur William Meyer. The supposed experimental production of hemo- 

 lymph nodes and accessory spleens. V. Studies on hemal nodes 241 



iii 



