authors' abstract of this paper issued 



BY the bibliographic SERVICE SEPTEMBER. 



THE PERIOD OF SYNAPSIS IN THE EGG OF THE 

 WHITE RAT, MUS NORVEGICUS ALBINUS 



BENJAMIN HARRISON PRATT AND J. A. LONG 



From the Laboratory of Zoology, University of California^ 



TWO TEXT FIGURES AND ONE PLATE 



CONTENTS 



Introduction 441 



Material and method 442 



General considerations 442 



The last oogonial division and early pre-leptotene changes 443 



Contraction figures 446 



The leptotene stage 447 



The synaptene stage 447 



The pachytene stage 448 



The diplotene stage 450 



The nuclei of the early growth period 451 



The centrosome and chromatoid body 451 



Discussion and conclusions 453 



Literature cited 455 



INTRODUCTION 



Of the very considerable literature on synapsis much relates 

 to vertebrates, but only a small amount to mammals. In nearly 

 all of the pubhcations on mammals synapsis in the male. is de- 

 scribed, the process in the ovary being investigated in only a very 

 few cases. In view of the importance of synapsis in its relation 

 to theories of heredity and to the behavior of the chromosomes it 

 has seemed worth while to extend the study to the female of an- 

 other mammal. Of particular interest have been the problems 

 of the presence of an accessory chromosome, of the identity of the 

 chromosomes throughout the series of changes, and ot whether or 

 not an actual pairing of chromosomes takes place. 



1 Aided in the preparation of most of the figures by the Department of Anatomy 

 of the University of California. 



441 



JOURNAL OF MORPHOLOGY, VOL. 29, NO. 2 



