AMITOSIS IN BONE CELLS 327 



1. Amitosis occurs in highly speciaUzed cells and is followed 

 by degeneration: 



Chun ('90) cited by Ziegler. 



Flemming ('91), '92). In wandering cells which are on road to ruin. 

 Von Rath ('91, '93). In spermatozoa. 

 Ziegler ('91). In intense secretory cells. 

 Toyoma ('94). In the testes of the silkworm. 

 Krompeeher ('95). In bone-marrow. 



Wilcox ('95). In giant spermatozoa "really come to naught." 

 Plate ('98). In dying cells of tracheal epithelium of Janelles. 

 deBruyne ('99). In ovarian follicle of Hemiptera and Orthoptera. 

 Wilson ('00). A secondary process in most cases. 

 Gross ('01). In germ cells of thirteen species of Hemiptera. 

 Payne ('12). In Gelastocoris, the cells which apparently multiply by amitosis 

 do not produce ova. 



2. Generative amitosis does occur and it is a normal method: 



Arnold ('83- '84) Bone-marrow cells and leucocytes. 



Lowit ('91) In leucocytes. 



Verson ('91) In blind end of testicular follicle of Bombyx. 



Frenzel ('91) In intestinal glands of crayfish. 



Paladino ('93, '95) The new formations of the placenta in mammals. 



Reguard ('00) In Sertoli cells and spermatogonia of rats. 



Camaniti ('03). In liver cells (as important as mitosis). 



Hargitt ('03). In hydroids. 



Klemensiewicz (03, '04.) In blood cells (as important as mitosis). 



Child ('04). In the developing tissues of Moniezia. 



Gurwitsch ('04). 



Maximow ('OS). Normal in mesenchyme cells of young dog embryo. 



Glasser ('08). In entoderm of Fasciolaria (during development he found 

 mitosis in 13 per cent and amitosis 87 per cent). 



Rubaschkin ('08). In mesenchyme of embryo in region where gonads later 

 form. 



Foot and Strobell ('11). In ovaries of Protenor. Cells become ova. 



Descilleuls ('14). In epithelial cells of viterine cornea. 



Arber ('14). In cortical cells of root of Stratiotes. 



McLean, ('14). In cortical parenchyma of aquatic angiosperms. 



Jordan ('13). In ciliated cells. 



3. Cells may divide by amitosis due to external conditions 

 and later divide by mitosis again: 



Meves ('91, '94, '9G). In spermatogonia of salmandra. Due to cold. 



Nathanson ('00). In plants external condition ether). 



Gerasimoff ('92). In Spirogyra (says nothing of their return to mitosis). 



