STUDIES OF REPRODUCTIVE ELEMENTS: II. ^Q\ 



spiiidle, sliowiiig thus their further division. The cytoplasm sur- 

 rounding each of the nuclei and archoplusnis is connected with the 

 others hy a fine network, like the protoplasm in the segmentation of 

 Leptodora eggs obserxed l)y W'ci.sfnanii. and by myself ( 37, Taf. II, 

 Fig. t^O). Fig. 1<S gi\es a side view of a four-nucleated stage, in 

 wliich the nucleus on the right side is already divided into two 

 daughter nuclei, while that on the left is in the spindle form. Fig. 19 

 represents a stage immediately succeeding this. Here, in this in- 

 dividual, is seen a pai'tial line of division of the entire body, marking 

 its surface into two hemisjjheres. A further stage is represented Ijy 

 Fig. '20, where we see six nuclei preparing to divide. Of these two 

 belong to one half and four to the other, showing thus that the 

 division of the buds does not occ.-ur quite regularly even at this early 

 stage. The first line of division, although now very laint, is still 

 clearly to be recognised. In the living condition the body of the 

 Noctiluca had been imperfectly divided into two portions at the 

 part where the nuclei lie. This is shown more distinctly in Fig. 21, 

 where ten nuclei are to be found. Of these six belong to one half 

 and four belong to the other. The partial line of division of the body 

 is also ])lainly to be seen in this specimen. Fig. 22 represents a 

 further stage of budding, viewed laterally. All the nuclei visible are 

 represented in this ligure, and their number is fifty-one, showing 

 again the irregularity of division. A further stage of sporulation is 

 seen in Figs. 2o-30. Figs. 23-26 are drawn from sections of nearly 

 ripe spores, while those represented by Figs. 27-30 are from prepara- 

 tions of entire spores, drawn under different magnifying powers. In 

 Figs. 25, 2G (the spore on the right hand side of the figure), and 

 27-30, the spore cells are quite separated from each other, and they 

 have all got a long flagellum springing out from the basal third of 

 the cell, where the archoplasm lies. 



