16 BOTANICAL GAZETTE [JULY 
time. Figs. 36 and 37 are merely sketches of the spindle fibers to 
indicate their general direction. Fig. 35 is an unusual case. A cone 
of fibers appears to have been formed on one side only of the nucleus. 
The fibers are coming in and finding attachment to the chromo- 
somes. The large nucleolus is still present, as well as two smaller ones. 
The most critical stages of reduction have now been described and 
the remaining stages will be taken up with less detail at this time, but 
will be presented in full in a later paper. The chromosomes are at 
first irregularly arranged on the heterotypic spindle. As already 
seen, during spindle formation many of the chromosomes are fre- 
quently separate and unpaired. The attraction between the chromo- 
somes which leads to pairing is evidently weak, so that it is doubtful 
if any pairing takes place at metaphase between chromosomes 
which had not previously paired. On the other hand, chromosomes _ 
which have once paired, no matter how early, appear to remain 
together until their separation in the metaphase of the heterotypic 
mitosis. Hence probably in many cases the chromosomes pass to the 
poles of the heterotypic spindle without having previously paired with 
each other, that is, they were merely lying loosely in the equatorial 
region of the spindle in metaphase, so that it was largely a matter of 
chance which pole any particular chromosome went to. This is 
believed to be a matter of prime importance in determining the final 
result of the reduction divisions in Oenothera, and the nature of the 
distribution of chromatin elements which takes place. Its possible 
significance will be pointed out in the discussion. Fig. 38 shows the 
chromosomes just being drawn into the equatorial plate of the hetero- 
typic spindle. In the examination of thousands of spindles in about 
this stage, one usually finds the chromosomes spread out in several 
planes along the long axis of the spindle. Of course some of these are 
early anaphase stages in which the chromosomes have begun their 
journey to the poles, but the condition is seldom found where the 
chromosomes are arranged regularly in pairs on the spindle. The 
daughter chromosomes seldom advance toward the pole ina single 
plane, as is the case in so many forms, but are more or less irregularly 
strung out along the spindle in their passage to the poles. This is in 
striking contrast with their behavior in the homotypic mitosis. 
Usually in the early anaphase of the heterotypic mitosis a longi- 
