18 BOTANICAL GAZETTE [JULY 
of preparations proves, while a few are ring form (fg. 30), and 
still others, having divided transversely at the apex of the V or 
the closed end of the U, exist as a pair of rods. 
As the chromosomes approach the nuclear plate the arms of 
the V- or U-shaped ones close together, and, usually at the same 
time, transverse division takes place at the closed end. In this 
way all the chromosomes become of nearly uniform shape, con- 
sisting of two parallel or nearly parallel rods, which become 
more or less fused along the line of contact. The result of this 
is to form a double chromosome, very broad and irregularly 
oblong, which resembles in a striking manner the paired chro- 
mosomes at the nuclear plate of the first or heterotypic division, 
though they are formed as a result of folding and transverse 
division instead of by longitudinal cleavage. As the paired — 
chromosomes are oriented on the nuclear plate, they usually 
become bent in such a way that the convex side lies toward the 
‘axis of the spindle, while the ends are directed outward, and the 
axis of the double chromosome is perpendicular to the axis of 
the spindle. The figure therefore presented by the metaphase 
of the second division is very much like that of the heterotypic 
‘division, and the only way in which one can determine that 
‘these belong to the second division is by the fact that there are 
two such spindles within the wall of the mother cell. Variations 
in their position in the monaster occur. One end of the chromo- 
some may be directed inward toward the axis of the spindle, so : ' 
that a few of them may be somewhat convolute; or the bent end : 
may lie tangentially at the periphery of the spindle; or the 
chromosome may be nearly straight and standing on one end, 
‘while the other end radiates outward. As the position of the | 
chromosome varies at the nuclear plate, so the figures presented ' 
during the anaphase vary, but the result is the same in each case. 
The broad chromosomes lying thus at the nuclear plate, their ! 
edges face the poles of the spindle; the threads of the spindle 
which pull on the chromosomes are attached to that portion of a 
the chromosome on either side which lies near the periphery of — 
the spindle. On those which are bent so that both arms of the — 
Se a 
