292 BOTANICAL GAZETTE [APRIL 
Degeneration may occur in any part of the gametophyte. Fre- 
quently the second primary derivative degenerates before the first 
(fig. 37). If sister primary cells are formed, the struggle resulting 
from their parallel development is generally so great that disorgani- 
zation of both results (fig. 32). Usually one gains the ascendency. 
Often, after as many as three cells have been formed, one of the 
antheridial groups is crowded against the wall; irregular cavities 
appear in the cytoplasm (fig. 31); the protoplasm contracts and 
accumulates in masses of globules; and the nuclei becomes massed 
or uniformly granular (figs. 33, 53). When an extreme develop- 
ment of the first antheridial cell occurs, the primary cell as well 
as the secondary antheridial cell may disintegrate (fig. 33). 
Mitoses 
There are two types of mitoses; that characteristic of primary 
divisions, and that of secondary divisions. The latter does not 
differ essentially from ordinary somatic mitoses; the former is 
quite distinctive in its characters. 
The nuclei and chromosomes are decidedly kinetic. Just 
before mitosis, the primary nucleus moves to a more or less polar 
position. Frequently it comes in contact with one of the primary 
walls (figs. 14, 15, 16, 43). There is the usual movement of the 
chromosomes to form the central plate at metaphase, and the 
separation of chromosome groups during anaphase. Aiter the 
two nuclei have been formed, the one which is polar retains its 
position, while the primary nucleus moves to its central or supra- 
central position (figs. 5-7; 19-25; 43-45). 
The changes in the volume of the nuclear space are very marked. 
During prophase a slight expansion is followed by a contraction 
(figs. 14, 15, 16, 28) which continues until the disappearance of the 
nuclear membrane. The chromosomes at the poles during early 
telophase aggregate into compact masses (figs. 4, 18, 47; 4g); the 
nuclear membrane is formed, and the nucleus expands until it be- 
comes three or four times its original size. There is an associated 
accumulation or disappearance of food particles in the surrounding 
protoplasm. This may be regarded as evidence in favor of LAWSON § 
(7) explanation of similar phenomena, namely, that they are due 
