146 A CYTOLOGICAL INVESTIGATION OF SOME SPECIES 
Doutbless more than 40 chromosomes can reach the nuclei of the 
pollengrains. Dwarfnuclei were not found in the tetrads or in the pol- 
lengrains. It is therefore evident, that the setting out of the pairing 
of a part of the chromosomes in the prophase of the division of the 
PMC. of G. G. N. G. causes an incomplete chromosome-reduction, so 
that in all division-stages chromosomenumbers higher than the pure 
haploid number are found. 
The irregular reduction division of Ardjoeno-cane 
In Ardjoeno-cane also, the pairing of an indefinite number of chro- 
mosomes can set out in the division of the PMC. This occurence howe- 
ver is much less apparent than in the case of G. G. N. G., because it 
extends over part of the PMC only, while the number of chromosomes 
remaining unpaired also, is usually much smaller than in G. G. N. G. 

Fig. 48. Fig. 49. 
Fig. 48. Metaphase of the heterotype division of Ardjoeno (irregular division) 
x 2300. 
Fig. 49. Anaphase of the heterotype division of Ardjoeno (irregular division) 
x 2300. 
Fig. 48 pictures a nuclear plate, containing doubtless 42 chromatine- 
elements, pointing therefore towards 4 unpaired chromosomes. In fig. 
49 one observes an anaphase from the side, in which approximately 10 
unpaired chromosomes, all split, safe one, lie on the spindle. This is for 
this kind an exception, the number of unpaired chromosomes usually 
being much smaller. 
