I 20 
Steil. — Apogamy in Nephr odium hirtipes , Ilk. 
anaphases and telophases in the usual order, a peculiar incomplete nuclear 
and cell division now occurs. 
In the large majority of cases only a number of the daughter chromo- 
somes in the equatorial plate pass to the respective poles of the broad-poled 
spindle. In other instances the chromosomes appear to pass but a short 
distance towards the poles. The resting nucleus in the former instance will 
be either kidney-shaped or dumb-bell-shaped (Figs. 30, 31, PI. VI), and in 
the latter spherical (Fig. 26, PI. VI). It is evident from the foregoing that 
the new nuclear membrane encloses all the nuclear material which in an 
ordinary division is distributed to two daughter nuclei. The new nucleus 
so established thus contains the diploid number of chromosomes. 
Fig. 25, PI. VI, was made from a longitudinal section of a sporangium. 
F'ive of the eight sporogenous cells are shown in the section, and in each 
case some of the chromosomes have passed to the poles of the spindle. In 
cell a all the chromosomes appear to have passed to the poles, but the next 
section of the same nucleus shows many chromosomes between the two 
apparently separate groups shown in this figure. Fig. 27 of PL VI shows 
a similar but later stage. Only four of the sporogenous cells are shown in 
this case. The outlines of the cells are already becoming rounded, which 
fact indicates that they are to function as spore mother-cells. The chromo- 
somes are beginning to anastomose preparatory to the passing of the 
nucleus into a resting condition. The nuclear membrane has already been 
formed and encloses therefore the diploid number of chromosomes. Later 
stages are represented by Figs. 28, 29, 30, 31, 32, 33, and 34, PI. VI. In 
some of the nuclei shown in these figures the nuclear material is beginning 
to pass into the resting condition. It appears that occasionally the nucleus 
passes into this condition before the nuclear membrane has been formed. 
It was impossible, however, to obtain any positive evidence on this point. 
It is not difficult to find in a sporangium of N ephr odium hirtipes nuclei of 
the different forms described in various stages of synapsis and in the 
heterotypic and homotypic divisions. It is certain that the cells with 
these nuclei function as spore mother-cells. 
During synapsis a large number of the nuclei of the spore mother-cells 
are spherical in form. The number of nuclei of the kidney-shaped and the 
dumb-bell-shaped types becomes progressively smaller as the spore mother- 
cells grow older. Unless the incomplete cell divisions to be described later 
progress too far, there is no reason to doubt that many nuclei, at first 
irregular in form, later become spherical. 
Frequently in the same sporangium spherical nuclei and nuclei of the 
irregular forms described are present. Often chromatin material in the 
different nuclei of the sporogenous cells in a sporangium is in the same 
stage. It appears, from an examination of numerous preparations, that in 
some instances the chromosomes in the equatorial plate of the eight-celled 
