i. The Significance of Sex. [ Feb, 
The phases of this cycle may be few or they may be many, and 
besides, the phase in which the nucleus rests may be in one case 
in one point of this cycle, in another it is a different phase of this 
cycle. But in all cases the cycle is made up of stages of fusion or 
of segmentation between the two extremes of one single nucleolus and 
of numerous granules. (The law is unchanged even if we sup- 
pose that the granules are the nodes of a reticulum.) Usually 
nuclear division follows that point in the cycle where the chro- 
matin is most condensed. Thus, even in the Remakian schema, 
this law is followed, as see Figs. 99, 100, 101. Cases like Figs. 
IOI, 103, 104, and karyokinesis in Metazoa are related to the Rema- 
kian schema by a compounding of the latter, for cach karyosoma fol- 
lows the Remakian schema. We thus see that direct division is to in- 
direct division asa unicellular or unisegmental animal is to one that 
is multicellular or multisegmented. Jf we study the cell-division 
of multinuclear Protozoa we find that the same laws hold. Opalina 
is an exception, and such forms as Polykrikos (Fig. 96), that have 
only nuclear division during cell-division, are connecting links to 
the far larger class of cases, where, as in Oxytricha (Fig. 95), 
Paramoecium (Fig. 9734), Stentor, etc., there is fusion of the 
nuclei (or of nuclear segments in moniliform endoplasts) before 
division and multiplication of these bodies preceding, during, or 
following division. In Paramcecium the resting phase concurs 
with the mononucleate phase. But even in the exceptions to this 
law there is fusion, when these forms encyst to produce spores 
(Fig. 97) by the successive or by simultaneous division of the 
fused nucleus. In such cases, as in conjugation of low forms, 
the phenomena may be facultative, the number of nuclei resulting 
from the fusion being one which varies from one to the original 
number, just as the resulting spores may vary in number. 
What is the meaning of this? Zt ts evident that we have here 
to do with conjugative phenomena. These self-same nuclei that 
with one form of cell-division fuse, may, in case of buds, be set 
free, as microgonidia to fertilize other gonidia. It may be that 
the granules and nuclei are in different parts of the cell subjected 
to different conditions, and thus come to vary slightly. If, now, 
the cell divided, the daughter-cells would differ, and ultimately 
new species be formed. But, as we find that if conjugation phe- 
_ nomena be left out in one place in the different modes of repro- 
