262 c. iSHiKAWA : nucleak division of noctiluca. 



Fig. 7. Penultimate stage of the division of spore-forming cells showing 

 the lengthening of the archoplasmic spindle. Zeiss' apochromatic lens with 

 compensation eye-piece 6. 



Fig. 8. Similar to fig. 7. 



Fig. 9. Last division of the same drawn under a high power. On the 

 right is represented a cell in which the archoplasmic fibres are still very 

 short ; on the left a daughter-cell which has just finished its division and 

 in which the fibres {fl') are in the process of elongation to form the 

 flagellum of the spore. Zeiss' apochromatic lens with compensation eye- 

 piece 12. 



Fig. 10. Penultimate division of the spore-bud in which two centro- 

 somes are very distinctly observable in each archoplasmic mass. Section 

 stained with iron-hrematoxylin and bordeaux. Zeiss' apochromatic lens 

 with compensation eye-piece 6. 



Fig. 11. Two ripe spores just leaving ofi' the mother-animal. Centro- 

 some (c) surrounded as usual by a clear space lies in the granular mass of 

 archoplasm which nearly fills the whole anterior portion of the spore. 

 Cytoplasm in the posterior portion shows a beautiful reticular or alveolar 

 structure. Zeiss' apochromatic lens with compensation eye-piece 6. 



Fig. 12. Spore-forming individual with a tripolar spindle but with the 

 nucleus in the usual resting condition, Zeiss' objective B with eye-piece 2. 



