AND SPECIES HYBRIDS OF THE GENUS SACCHARUM 281 
chromosomes in the daughtercells so, of course, becomes smaller than 
that in the mothercell, but the reduction takes place in an entirely 
abnormal manner. A nuclear wall is now formed around the chromo- 
somes in the daughtercells. The diads can have a different aspect. In 
fig. 66 one is seen with one of the nuclei laced around the middle. 

Fig. 65. 
Fig. 65. Formation of a diad ina PMC of G. G. N. G. dividing abnormally x 1750 
Fig. 66. Abnormal Pollen-diad of G. G. N..G. x 1750. 
In the strangest manner tetrads are now apparently formed, which 
frequently contain more than 4 cells. Fig. 67--70 show examples; a 
great many others could have been added, but it is of no use to dwell 
upon these abnormalities, as there is little chance that they should end 
in the formation of fertile pollen. 
Fig. 67 shows a „diad”, one cell of which contains a large nucleus 
with fully 40 chromosomes, while the other cell has begun to divide; 
this division proceeded in so irregular a way, that at one side 6 chro- 
mosomes arrived, while at the other end more than 40 were crowded 
close together, the cell wal between these two groups has been formed 
but partly. — 
Fig. 68 shows a ,homotype’”’ division with three nuclear plates with 
clearly unequal chromosomenumbers. This division will probably pro- 
duce a hexad and it is questionable whether it will end at that. 
A hexad is figured in fig. 69. In five cells of very unequal size hardly 
