296 



JSfaohide Tatsu. 



7 



*• 



• • 





Fig. rV (X903). 



7, Section of an enucleated fragment, in which a single 

 cytaster has made its appearance. Notice enlarged centrosome 

 and many centrioles in it. <?, section of the enucleated frag- 

 ment, represented in Fig. if, with central clear area containing 

 many cytasters and yolk-islands. 



the yolk part, so that in 

 sections as many inden- 

 tations are present as 

 the number of intervals 

 between two asters. It 

 should be noted that 

 the yolk granules near 

 the clear space in over 

 extracted preparations 

 shows a radial arrange- 

 ment (Dotterstrahlung 

 of Hacker), and clear 

 streaks run between 

 the rows of yolk gran- 

 ules. These streaks, 

 however, do not go far 

 into the yolk layer. 



In both the types a 

 and c the structure of 

 the cytasters is very 

 similar, so much so 

 that it is hardly neces- 

 sary to describe them 

 separately. The only 

 difference between 

 them lies in that in 

 the type a the rays are 

 much stronger than 

 those of the type c. 

 Some of the cytasters 

 are drawn with a 

 higher power. Fig. 9a 

 and 9b are the same 

 ones shown in Fig. 

 6; the former is the 

 upper one and the lat- 

 ter the lower one. Fig. 

 9c is from a section of 

 another fragment in 

 which only three large 



