386 



Naohide Yatsu. 



Fig. C. Five stages of the first cleavage, x 400. 1. Anaphase of the 

 first cleavage mitosis. Crossing of raj's, and the position of the spindle. 

 Difference in distance between two centrioles at either end ; 2. Telophase 

 of the first cleavage mitosis. The ceutrosome has enlarged and been bent 

 downwards. The crossing of rays has begun to loosen. A faint indication 

 of fountain figure is seen at the pole regions; 3. Telophase, a vertical section 

 through the poles and a centriole. Constriction has begun on both the animal 

 and vegetative sides. Sheath spindle has been formed. Fountain figures 

 at the poles of the spindle have become more distinct ; 4. Telophase, a hori- 

 zontal section through three centrioles (about the same stage as 3). Sheath 

 spindle is very well formed. Centrosome has greatly enlarged. The distance 

 between the rows of karyomeres is approximately the same as the original 

 length of the spindle; 5. Late telophase (a vertical section). Sheaf rays 

 have been formed. Fountain figure in the equatorial rays. 



