CONTENTS 



No. I — January, 190Q 

 Ada Springer 



A Study of Growth in the Salamander, Diemyctyles viridescens i 



Edmund B. Wilson 



Studies on Chromosomes. IV. The "Accessory" Chromosome in Syro- 

 mastes and Pyrrochoris with a Comparative Review of the Types of 

 Sexual Differences of the Chromosome Groups. With Two Plates 

 and Two Figures in the Text 69 



N. M. Stevens 



Further Studies on the Chromosomes of the Coleoptera. With Four 

 Plates loi 



An Unpaired Heterochromosome in the Aphids. With Two Plates 115 



David Day Whitney 



The Effect of a Centrifugal Force upon the Development and Sex of 

 Parthenogenetic Eggs of Hydatina Senta. With One Plate 125 



Observations on the Maturation Stages of the Parthenogenetic and Sexual 

 Eggs of Hydatina Senta. With Five Figures in the Text 139 



No. 2 — February, 1909 

 Edmund B. Wilson 



Studies on Chromosomes. V. The Chromosomes of Metapodius. A 

 Contribution to the Hypothesis of the Genetic Continuity of Chromo- 

 somes. With One Plate and Thirteen Figures in the Text 147 



Merkel Henry Jacobs 



The Effects of Desiccation on the Rotifer Philodina Roseola. With One 

 Figure 207 



J. F. McClendon 



Protozoan Studies. With Two Plates 265 



Charles R. Stockard 



The Development of Artificially Produced Cyclopean Fish — "The Mag- 

 nesium Embryo." With One Plate and Sixty-three Text Figures. . . . 285 



