1922] SEARS—TARAXACUM 321 
duality represents a splitting and not a pairing. These facts seem 
sufficient to warrant more critical comparison of prophases in 
sexual and parthenogenetic species of Taraxacum before deciding 
that parasynapsis is actually the source of duality in spireme 
threads of the former. Moreover, the completed synapsis in 
sequence A, as well as the delayed pairing in sequence B, is end to 
end, rendering any assumptions still more difficult. 
3. We have seen that ameiosis does not involve the complete 
elimination of sex. Rather it involves a retardation and partial 
inhibition of sex expression. The least degree of inhibition gives 
us sequence A, practically a normal reduction division with synaptic 
mates pairing only a little more slowly than is usually the case. 
A greater degree of inhibition obviously occurs in sequence B, the 
delay being more marked. Whatever the ultimate cause of such 
delay, there can be no question that it amounts to a persistence of 
chromosome individuality, which at segmentation supersedes the 
individuality of the nucleus as a dominant phase. The nature of 
sex inhibition in sequence C is more complex. Synapsis is slow 
and of varying perfection. It is marked by an elongation of the 
nucleus, clearly indicating a premature expression of polarity. 
We may conclude, therefore, that encroachment upon sex is 
progressively increasing. 
ype D is readily interpreted, in view of these intermediate 
conditions, as the still earlier and more powerful expression of 
polarity at the segmentation stage. Not only does the nucleus 
become greatly elongated and eventually pulled apart, but the 
spireme split begun in prophase is never even temporarily overcome 
y the forces making for chromosome individuality. This is 
evidenced by the presence of X and Y forms, already noted. Such 
interpretation of the amitosis in sequence D by no means vitiates 
any possibility that it may be a matter of emulsification, as 
Suggested by coupling the work of NATHANSOHN and that of 
Bonns. It merely involves a third, and not unreasonable factor, 
enzyme action, as a means of upsetting the delicate balance between 
the forces which we ignorantly know as individuality, polarity, 
and sex. That the dominance of polarity is not likely to be:perfect 
seems probable from the nature of the factors which it overrides. 
