110 SCHAFFNER: SEXUAL STATE IN SAGITTARIA LATIFOLIA 
lems of sex. The term allosome implies no special hypothesis 
as to the nature of these bodies. From a general or funda- 
mental point of view, every chromosome of a sexual organism is 
a ‘‘sex chromosome’’; for apparently in gametes the primary 
sexual property of attraction is possessed to a high degree by 
the chromatin. The attractive property disappears or is neu- 
tralized when the two sex nuclei have united. Now at synapsis, 
in the reduction division, this primary attractive property 
develops again but the attraction is between the specific pairs of 
chromosomes in the diploid nucleus, whether the cell be an 
oécyte or spermatocyte, a megasporocyte or microsporocyte, 
or a more primitive homosporous sporocyte, zygospore, or 
primitive odéspore. Attractive properties appear between the 
specific pairs of chromosomes and continue until the extreme 
folding or looping stage of synapsis when the two members of 
the diploid chromosome seem to be neutralized and are then 
soon separated by the reduction spindle. There is no need of 
assuming that this attractive property of the synaptic chromo- 
somes is anything different from the sexual attraction shown at a 
previous stage between the entire male and female nuclei 
which are usually in the resting stage during fusion. The dimor- 
phism of allosome pairs, together with their apparent differences 
in complements of hereditary factors, may have a decided in- 
fluence over the attractive states which arise in them, both 
while they are in synapsis and while they form a part of the 
chromatin masses of conjugating male and female nuclei. And 
this specificity may lead to differential attraction between the 
gametes. 
The evolution of sex from the primitive, physiological 
isogamous condition has come about by the shifting of the 
origin of the male and female states into an earlier and earlier 
stage of the sexual cell ontogeny. In case of the primary or 
gamete sexual characters, the lowest tvpe shows gametes with 
no apparent morphological difference. The sexual state evi- 
dently does not arise until the development of the gamete is 
complete. By a succession of forms in many independent lines 
the extreme dimorphism of egg and sperm is soon attained. 
This progression can be explained by assuming that the origin 
of the sexual state arises at an earlier and earlier stage of the 
ontogeny of the gamete as stated above. When it arises with 
