I5 2 BOTANICAL GAZETTE [march 



in the superficial cells or in the antheridium initial from which the 

 central cell is derived, and consequently this structure may originate 

 in the central cell. It does not seem to play any important role in 

 the nuclear division. As successive mitoses proceed, it becomes 

 more faintly stained, less conspicuous, and finally becomes impossible 

 to differentiate by staining; but in rare cases it still remains, filling the 

 whole cytoplasm up to the eight- or sixteen-cell stage of the sperma- 

 togenous cells. A structure of similar appearance was observed in 

 the central cell of the archegonium (figs. 41, 41a). 



The spermatid mother cell is characterized by the first appearance 

 of blepharoplasts. In general, the spermatogenous cells, in spite of 

 their small size compared with the vegetative cells of the prothallia, 

 contain large nuclei. The cytoplasm seems generally destitute of 

 plastids and has a very fine fibrillar structure, and the membrane is 

 delicate. The mitoses which take place in the spermatogenous cells 

 are conspicuous on account of the comparatively large amount of 

 chromatin, but otherwise they resemble those of the vegetative cells. 

 In the telophase of the mitosis, previous to the formation of the 

 spermatid mother cell, the groups of daughter chromosomes, having 

 reached the poles, begin to be vacuolized. Detailed study of this 

 stage shows that the formation of the membrane around the mass of 

 vacuolized chromosomes, or young daughter nucleus, is a little delayed 

 in the polar region, which appears concave from the side view (fig. 11). 

 The nucleus when viewed from the pole shows that the chromatin 

 material resulting from the vacuolized chromosomes is very scanty 

 in the polar region and three or four nucleoli are always present 

 (figs. 12, 73); such a structure of the nucleus may be regarded as a 

 kind of polarity. If there could possibly be any migration of nucleoli 

 from the interior of the nucleus to the cytoplasm, it would certainly 

 occur in such a critical stage of the nucleus, but there was not observ- 

 able any peculiar differentiation within the cytoplasm that might 

 warrant the supposition. 



As the young daughter nucleus grows in size and assumes a spheri- 

 cal form, the chromatin loses its peculiar arrangement and becomes 

 transformed into the irregular ragged reticulum of the resting condi- 

 tion. Then there are observed by their differential staining two 

 small bodies, the primordia of the blepharoplasts, lying within the 



