( 827 ) 



may nevertheless still l)c ol)served for a long time. In some cases 

 the nnclens of this cell divides once more, in a plane perpendicular 

 to that of the previous division, so that the equatorial plane of the 

 second division is in the longitudinal direction, with respect to the 

 ovule. Perhaps this division also takes place in other cases, in which 

 the two nuclei cannot be seen on account of the unfavourable direc- 

 tion ot the section and in consequence of the rapid degeneration 

 of the cell. Only in a single instance 1 have thought that I 

 observed a cell division following the division of the nucleus in the 

 upper cell. 



The lower of the above-mentioned two cells is the embryo-sac. 

 Having regard to the size of the pseudo-embryo-sac, it is remarkable, 

 that the real embryo-sac increases but little in size, and always 

 remains situated in that upper part of the nucellus, which projects 

 beyond the inner integument ; it remains of course surrounded by 

 the layer of epidei-mal cells, which later are only compressed and 

 flattened more and more, so that they become scarcely visible. 



The nucleus of the embryo-sac soon divides again. Only a single 

 division was observed, and then the fixation did not allow many 

 details to be made out; it can hardly be doubted, however, that this 

 must be a homoiotypic division of the nucleus. The axis of this 

 spindle is longitudinal with respect to the ovide and thei-efbre also 

 with respect to the embr} o-sac. The lower of the two nuclei, which 

 are formed, is seen to degenerate in the anaphases of the division, 

 by a strong clumping of the chromatin masses, so that the latter 

 come to lie at the base of the embryo-sac as a structureless chro- 

 matin-like clump, which stains deeply. This is evidently all, that can 

 here be seen of the antipodal apparatus and of the lower polar 

 nucleus. I shall call this nucleus the antipodal nucleus of the 

 embryo-sac. 



In contra-distinction to the last-named, the other nucleus assumes 

 a normal shape and is prominent on account of its size. Soon after- 

 wards there follows another division, of which I have been able to 

 see the various stages. The axis of the spindle is this time also 

 longitudinal to the embryo-sac and ovule. This division is not at first 

 followed by a cell division, but afterwards each of the two daughter 

 nuclei divides again. The actual process of division I have not 

 observed, but have only found four nuclei; the second division 

 evidently takes place very rapidly, for I have looked through hundreds 

 of preparations of about this age, without getting the actual stage of 

 division. This second division takes place in such a manner, that 

 the axes of division are perpendicular to each other; for the upper 



