NUCLEAR DIVISION OF NOCTILUCA. 261 



Explanation of Plate XIX. 



Figures 2, 3 and 12 were drawn from life ; all the others, with the 

 exception of fig. 10, from entire preparations treated with Flemming's 

 fluid and iron-lia3matoxylin with or without bordeaux. 



Fig. ] . Part of a specimen nearly completely divided into two daughter- 

 individuals, which are still connected by a narrow bridge of protoplasm. 

 Close to the nucleus is seen a large archoplasmic mass from which a short 

 tentacle (t) has just been formed. Zeiss' apochromatic lens with eye-piece 6. 



Fig. 2. A living specimen, just divided and with the daughter -indivi- 

 duals still connected by a broad bridge of cytoplasm. At one side of the 

 nucleus is seen a dark archoplasmic mass (a) from which the tentacle {t) is 

 just being developed. Zeiss' objective B with eye-piece 2. 



Fig. 3. Similar to fig. 2, but the tentacle (t) slightly more advanced 

 in development. 



Fig. 4. Part of the central plasma from an individual nearly completely 

 divided, the daughter-individuals being connected only by a very narrow 

 bridge of cytoplasm which was severed during treatment with the reagent. 

 The tentacle {t) is situated as before in the median part of a darkly stained 

 archoplasm. Besides this, the teeth {tli) and flagellum {fl) are already 

 formed. The latter also developes itself out of the archoplasm. Zeiss' 

 apochromatic lens with compensation eye-piece 6. 



Fig. 5. One of the spore-forming spindles from a stage of 18 cells, 

 of which 10 were situated on one side and 8 on the other. The cen- 

 trosome (c), radial fibres (r./.) and an accumulation of nucleoplasm at the 

 ends of chromosomes are distinctly observable. Zeiss' apochromatic lens 

 with compensation eye-piece 12. 



Fig. 6. Similar to the preceeding figure, but the two dividing nuclei 

 still connected with each other. Two centrosomes (c) still in connection 

 with each other are seen in only one of the four archoplasmic masses. 

 Radial fibres (î*. /.) are distinctly to be seen. Zeiss' apochromatic lens with 

 compensation eye-piece 6. 



