Trow . — The Karyology of Saprolegnia. 627 
from the stained microsomata and nucleo-hyaloplasm which 
surrounds them, and thus come to lie free in the protoplasm. 
At this stage no nuclear wall can be detected, although there 
is a clear space around the pair of rods : in the figures the 
boundary of this space is represented by a line, which must 
not be regarded as implying that the nuclear wall persists, 
though no longer evident. The evidence rather points to the 
conclusion that the nuclear wall is ruptured, and that the 
stainable nucleo-hyaloplasm, together with the deeply-coloured 
microsomata which surround the nucleus, are dispersed in the 
protoplasm, retaining however, for a time, their capacity for 
absorbing nuclear stains. These points will be appreciated so 
much the better if Fig. 8 a , h , c , and d , and Fig. 9 be consulted, 
the latter of which represents one section of the oogonium and 
antheridia in which these phenomena were specially studied. 
In Fig. 8 a the stained mass (nucleo-hyaloplasm, &c.) still 
lies in contact with the rods ; in c it has entirely disappeared ; 
and in d it seems further as if one of the rods were undergoing 
degeneration, as it does not stain deeply like its fellow. It 
will be noted, too, that the rods ultimately assume a spherical 
form. 
Fig. 10 a and b deserves special study, as that of a stage 
immediately following upon the one represented in Fig. 9. 
Four of the pairs of now spherical rods are still to be seen, 
and are stained deeply ; three of the pairs have undergone 
complete division so as to give rise to six new small daughter- 
nuclei, which are still, however, arranged in groups of two ; 
while in addition there are six small solitary nuclei. One 
frequently notices in preparations of this stage that one or 
both of the paired rods stain badly ; and occasionally, as at 
deg. n. in Fig. 10 a, we can just discern pairs in which the 
half-chromosomes have become so excessively small as to be 
scarcely recognizable. The stained nucleo-hyaloplasm and 
microsomata are still to be recognized, associated with those 
nuclei that were later than the others in entering upon 
division. 
It would be natural to anticipate that, in consequence of 
