AUTHOR 8 ABSTRACT OF THIS PAPER ISSUED 

 BY THE BIBLIOGRAPHIC SERVICE, NOVEMBER 7 



AMITOSIS IN THE CILIATED CELLS OF THE GILL 

 FILAMENTS OF CYCLAS 



FRANK HELVESTINE, JR. 



De-partment of Histology and Embryology, University of Virginia 



TWO PLATES (seven FIGURES) 



INTRODUCTION 



The purpose of this investigation is further to test the vahdity 

 of the hypothesis first formulated by v. Lenhossek and by 

 Henneguy ('98) that the basal bodies found in ciliated cells are 

 derived from the centrosome, and particularly the corollary of 

 this hj^pothesis, as expressed by Jordan ('13), that ciUated 

 cells, in consequence of the loss of their centrosome through 

 partition in the formation of basal bodies, must necessarily 

 proliferate by amitosis. 



Jordan ('13) supports the hypothesis as regards especially 

 the ciliated epithelium of the ductuli efferentes of the white 

 mouse, and shows for the first time that the cells in this region 

 multiply exclusively by direct division. In no case was he able 

 to demonstrate a centrosome or a mitotic figure. 



Saguchi ('17) confirms the observation of exclusively amitotic 

 division in ciliated cells of vertebrates, but he does not agree with 

 the view held by Jordan that these cells divide amitotically 

 because the centrosome has been used up in the formation of 

 the basal granules. He concludes that there is no genetic relation 

 between basal bodies and the centrosome. He states also that 

 the basal granules are formed by differentiation from mitochon- 

 dria, both in vertebrates and in invertebrates. He further 

 declares that in invertebrates ciHated cells multiply by mitosis 

 exclusively. It may be stated at once that Saguchi's descriptions 

 and illustrations do not adequately support his conclusions. 



103 



