THE SOMATIC MITOSES OF THE MOSQUITO CULEX 



PIPIENS 



ROBERT T. HAXCE 



Zoological Laboratory, University of Pennsylvania 



TWO PLATES 



CONTEXTS 



I. Introduction 579 



II. Technique 580 



III. Observations 582 



A. Prophases 582 



B. Metaphase 583 



C. Anaphase 5S4 



D. Artefacts 584 



IV. Discussion of results and of the literature 584 



V. Summary ; 5 s 7 



VI. Bibliography 587 



INTRODUCTION 



The great mass of cytological work has been done on the germ 

 cells, partly because of the abundance of mitotic stages found 

 there, partly because of the greater ease of manipulating this 

 tissue, but largely because of the great theoretical importance 

 of the processes here visible. Beyond a few general sorties into 

 the field of somatic cell division, which detennined that the body 

 chromosomes were usually present in the same number as in 

 the reproductive cells, and were, in some instances, at least. 

 similar morphologically, little has been done in the way of 

 thoroughly working out the mitotic mechanism from prophase 

 to telophase. 



The ideal investigation into somatic cytology would follow 

 the chromosomes of the fertilized egg as it evolved into the 

 organism and as the cells differentiated into specialized tissues, 



579 



