﻿1903] NUCLEAR MEMBRANE 319 



of contact of the karyolymph with the cytoplasm we can observe the lirst 

 indication of the nuclear membrane. 



Fig. 7. Shows a still later stage where the karyolymph has increased 

 considerably arid the chromatin has become divided to such an extent as to 

 expose the cytoplasm to the karyolymph on all sides, and as a result we have 

 a complete membrane formed ; the daughter nucleus is now perfectly spheri- 

 cal, containing all the elements of a mature nucleus. 



Fig. 8, Shows a daughter nucleus with the chromatin in the spirem stage ; 

 this is after the cell plate has been formed and the accumulation of the 

 granular zone around the daughter nucleus indicates that it will soon 

 prepare for the second division. 



Fig. 9. An archesporial cell of Eqiiisetum limosiim ; the chromosomes 

 have fused together and each daughter nucleus consists of a large irregularly 

 shaped mass of chromatin. 



Fig. 10. The same at a later stage, showing several lacunae containin 

 karyolymph within the chromatin mass of each daughter nucleus. 



Fig. II. a still later stage showing an increase in size and number of the 

 lacunae; some of the latter have increased to such a size as to extend beyond 

 the chromatin, and as a result the cytoplasm becomes exposed to the kary- 

 olymph ; the result is the appearance of a membrane at the region of contact 

 of the cytoplasm with the karyolymph. 



Fig. 12. Shows a stage where the volume of karyolymph has increased 

 to such an extent as to completely surround the chromatin; the cytoplasm 

 comes in contact with the karyolymph on sides resulting in the formation of 

 a complete membrane about each daughter nucleus. 



Fig. 13. Showing the vacuolar appearance of the mature nucleus of the 

 archesporial cell of Equisetum ; it also shows the relative size of these nuclei 

 to the cytoplasm. 



