AUTHOR S ABSTRACT OF THIS PAPER ISSUED 

 BY THE BIBLIOGRAPHIC SERVICE, MARCH 20 



RELATIVE NUCLEAR VOLUME AND THE LIFE-CYCLE 

 OF HYDATINA SENTA^ 



A. FRANKLIN SHULL 

 Zoological Laboratory, University of Michigan 



ONE FIGURE 



CONTENTS 



Origin of the idea of significance of nuclear volume 284 



Applications of the idea 285 



Relative nuclear volume in the life-cycles of parthenogenetic animals 288 



Hydatina as material for the study of the Kernplasmarelation in a partheno- 

 genetic animal 293 



Tests employed 295 



Periodicity of male-production 295 



Age of individual 296 



Effect of manure solution 297 



Tissues examined for Kernplasmarelation 297 



Method of measurement and precautions in study of Kernlasmarelation 298 



Oocytes 298 



Stomach-intestine 299 



Yolk gland 299 



Measurement of the drawings 300 



The personal equation 301 



Acknowledgments 301 



Nuclear volume and periodicity of male-production 301 



Yolk gland 301 



Stomach-intestine 304 



Oocytes 305 



Nuclear volume and age of individual 309 



Yolk gland 309 



Stomach-intestine 311 



Oocytes 311 



Effect of manure solution on nuclear volume 312 



Comparison of male-producers and female-producers 313 



Discussion 313 



Summary 318 



Bibliography 320 



* Contribution from the Zoological Laboratory of the University of Michigan. 



The many thousands of computations made in the preparation of this paper 

 were mostly done on a calculating machine furnished by the trustees of the 

 Elizabeth Thompson Science Fund, to whom I desire to express my gratitude. 



For aid in providing much of the routine labor involved in the study I am glad 

 to acknowledge my indebtedness to a grant from the Bache Fund. 



283 



