632 Wisconsin Academy of Sciences, Arts, and Letters. 
appeared and the spirem is now a single thick thread. No defi¬ 
nite arrangement of the spirem loops can be made out hut the 
spirem is distributed in such a manner that no regions denser 
than others are present in the nucleus. 
This stage has been described as occurring in the heterotypic 
prophases of practically all plants studied as to reduction. 
Still Grates (30) and Davis (18) have recently reported that in 
the Genus Oenothera the uniformly distributed spirem follow¬ 
ing synapsis is lacking, synapsis being followed at once by an 
irregularly distributed thick spirem. Davis is inclined to think 
that this expanded stage and the second contraction stage which 
follows it are both parts of the synaptic stage. This usage of 
the term synapsis seems to be new with Davis. 
As the spirem begins to change from the uniformly distri¬ 
buted condition to a condition of unequal distribution it again 
appears double (Figs. 19 and 20). This separation appears 
first as a more transparent line containing less stain, which ex¬ 
tends longitudinally through the middle of some parts of the 
spirem thread. The earlier stages are best demonstrated in 
preparations stained in Heidenhain’s iron alum haematoxylin 
stain. Slides stained in Flemming’s triple stain retain the 
stain more tenaciously between the halves of the spirem so that 
the longitudinal splitting shows more or less obscurely. 
During the period of the uniformly distributed spirem the 
thread increases in diameter and at the same time probably 
shortens somewhat, though there is no conspicuous shortening. 
The increase in diameter is out of proportion to the shortening 
of the spirem and it seems clear that the amount of stainable 
material in the nucleus has been largely increased during this 
period. 
This stage of the uniform distribution of the spirem does not 
seem to be of long duration for though not at all uncommon in 
my preparations it is quickly succeeded by a second contraction 
stage. A, dense aggregation of a part of the spirem in the cen¬ 
ter of the nuclear cavity appears, with broad irregular loops or 
coils extending out from this central mass to the periphery 
(Figs. 21 and 22). This stage corresponds in appearance and 
