AND SPECIES-HYBRIDS WITHIN THE GENUS SACCHARUM 307 
the cross S. officinarum X S. spontaneum posses in their gonotokonts 
a number of bivalent chromosomes, which probably is a little inferior 
to 70. 
From two species with unequal chromosomenumbers, one therefore 
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Fig, 91. 
Fig. 91. Anaphase of the heterotype division of an individual from the cross 
Saccharum officinarum x S. spontaneum (individual G 107 = Striped Prean- 
ger x Glagah alas Troeno) x 2300. 
sees here arise forms with equal chromosomenumbers, and such which 
are higher than those of either of the parents. 
One could imagine that some kind of process takes place in the 
zygote-nucleus of the hybrids, which causes the appearance of a new 
set of chromosomes surpassing in number the sum of the haploid num- 
bers, which during fertilisation came together, after a loss of their indi- 
viduality on the part of the two haploid sets. 
It seems however to me very improbable that something of the kind 
should have taken place. No such cases are known to me from the 
litterature, while no other indications make such a thing probable. 
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His m2. 
Fig. 92. Anaphase of the heterotype division of Kassoer X 2300 
Another supposition is possible, which seems to me to be a probable 
one. If one fixes the haploid chromosomenumber of the hybrids at 68 
