90 



CONKLIN. 



[Vol. XIII. 



spreading throughout the cell. The whole cell stains very much 

 more uniformly than does a normal cell, and in this regard these 

 tip cells resemble the polar bodies in the stages where they are 

 last seen and where they are undoubtedly degenerating. Fur- 

 ther stages in the degeneration of the tip cells are shown in Figs. 

 69, 70; in the former the two tip cells are pushed still further 

 above the level of the surrounding cells, while in Fig. 70 they 

 are separated from each other and practically detached from 

 the egg. I have observed this process in only a few eggs of 

 the species C. plana and am not wholly convinced that it is a 

 constant feature. Such a phenomenon is certainly very re- 

 markable and unusual, and I am not prepared to draw any 

 conclusions as to its significance. 



In this last stage, then, in which the cross can be recognized 

 as a whole, it is composed of the following cells : 



Apical \ 



Peripheral Rosette \ 



Inner 4 



Outer 4 



Inner 4 



Outer 4 



Anterior Arm 



Basal 



Middle 



Transverse Arms - 



Inner 2 



Outer 2 



Inner 2 



Outer 2 



Inner .... 2 



Basal 



Inner 2 



_ Outer 2 



Middle 2 



,. ( Inner .... 2 



Intermediate ■{ ^ 



i Outer .... 2 



Tip (Terminal) 2 



16 



Intermediate 4 ^ 



( Outer. ... 2 



Tip (Terminal) 4 



Right Arm . . i6 



Left Arm ... 16 



32 



Posterior Arm 



C Basal i 



J Middle i 



I Intermediate o 



I Tip (Terminal) 4 



Total 



66 



