18 BOTANICAL GAZETTE [JULY 
at various angles to each other. Spindle formation is the same as for 
the heterotypic mitosis, except that the spindles are smaller. In | 
regard to the chromatin, suffice it at present to say that the chromo- 
somes of the homotypic prophase show the same general types and 
are often identical in appearance with those of the heterotypic telo- 
phase. There can be no doubt that the bivalent bodies which appear 
on the homotypic spindle are the same bodies that were present in the 
telophase of the heterotypic. Fig. 47 shows an early anaphase of the 
second mitosis, the members of each pair having just separated. One 
of the small nucleoli appears by one of the spindles. 
IRREGULARITIES 
In fig. 39 spindle fibers are seen in the cytoplasm by the side of the 
spindle in anaphase. This may be connected with a condition which 
is illustrated in fig. go. Six such cases were observed in which a 
regular spindle occurred at the side of the mother cell instead_ of 
between the daughter nuclei, after the partial or complete disappear- 
ance of the heterotypic spindle. Some of these cases were in the telo- 
phase of the heterotypic spindle (fig. 40); others were in the prophase 
of the homotypic. In these cases the spindles were regularly formed 
and rather sharp-pointed and occupied the same position at the side 
of the cell; of course they contained no chromosomes. The method 
of their origin is unknown, but it seems probable that they are con- 
nected with the condition observed in fig. 39. Mother cells which 
probably indicate an intermediate condition, in which irregularly 
arranged fibers were found at the side of the cell, were occasionally 
observed. They may merely indicate a persistence of the kinoplasm 
of the heterotypic spindle after its function has ceased, but their 
structure appeared remarkably definite in most of the cases observed. 
_ A single case of extra nuclei in the pollen tetrad was observed in 
O. rubrinervis. These have been previously described in O. lata 
(11), where they are common occurrences in connection with pollen 
degeneration. The single case observed in O. rubrinervis is sketched 
in fig. 42. Two small nuclei are present in addition to the four 
larger ones composing the tetrad. The nuclei had passed too far 
into the resting condition to count the chromosomes in each 
nucleus. 
