I04 



LECTURE VII. 



'The division of the nuclear disc (which consists of nuclein rodlets) is ac- 

 complished in the equator, and both halves separate from one another. Elements 

 which lie in the equatorial plane, or run through it, undergo division. With granules, 

 rods, and rodlets, this takes place simply by constriction. If the nuclear disc 

 consists of accumulated granules or rodlets, one part goes over on the one side, the 

 other part on the other. The process is more complicated in nuclear discs which 

 present filaments placed equatorially. These form mostly two or more legged 

 figures, with the ends of the legs turned outwards. The figures become doubled 



Fig. los.-Changes of the cell-nucleus during division. 1—3 from the endosperm of Nolhoscoydm 

 friLerans; 4-8 from Alluim odormK. The dark portions are the Nuclein (after Flemminff: strongly 

 magnified). ' s « )■ 



into two similar ones, or now pass over to the corresponding daughter-nuclei in 

 such a manner that their fused ends are directed towards the pole, their free ends 

 towards the equator.' 



' During the development of the daughter-nuclei,' proceeds Strasburger, ' they 

 are usually nourished at the same time from the surrounding protoplasm, that 

 they may grow up to the size of the mother-nucleus. This may be followed very 

 well in Spirogyra, on account of the free suspension of the nucleus in the cell. All 

 the prptoplasm collected at the polar side of the daughter-nucleus, and here forming 



