SEGMENTATION 



15 



underlying, unflegmented, yolfc ( Ki.^. '.', <"> ;md in surface view the 



blastoderm a-sumes the appearanc-e shown in Fig S, 1). 



I'p ti a.nd including the seventh division mitosis takes place 



B 



$&'. .. : -;;i ; - 



'?"' 



Fie. !. \'ci tical sections tlirnu^li Kl:isni(il.ran<-h blastoderms illustrating tin 1 process of 

 segmentation. (After Riickert, 1899.) 



\. 0, I', K, Torpedo ; 1!. . 



; F, (i, I 1 , -latin ru*. \'., F, and G are sagittal sections with j>osterior 

 edge of blastoderm tn th- 1 ri-ln. 



practically synchronously throughout tin* blastoderm. In Torj'/<> 

 Riickert (1899) -found that even in the ninth division the majority 



of the nuclei still divided synchronously ,-nid lliat in some eggs the 

 same was the ease with the tenth division but in any case appmxi- 



