394 A CYTOLOGICAL INVESTIGATION OF SOME SPECIES 
§ 2. The cytology of some hybrid individuals of Saccharum officinarum X 
S. spontaneum 
I have made a preliminary investigation of the chromosome-number 
of 5 hybrid individuals from crosses of S. officinarum X S. spontaneum 
and of Kassoer-cane. I found the haploid number to be approximately 
68 to 70. At first I tried to explain this number on the assumption, that 
about 28 sugarcane chromosomes conjugate in the prophase of the 
heterotype division with 28 glagah-chromosomes and that 12 sugarcane 
chromosomes and 28 glagah-chromosomes remain unpaired.This would 
cause 68 chromatine-elements to appear in the nuclear plates. It was 
soon found however, that the number of gemini in the diakinesis- 
nuclei is doubtless considerably larger than 28, although in diakinesis 
also, approximately 68 to 70 chromatine-elements are present. It even 
seemed probable that pretty nearly all chromatine-elements were biva- 
lent. Fig. 88 shows a diakinesis-nucleus of a hybrid individual from the 
cross sugarcane Striped Preanger X glagah Alas Troeno. Although the 
whole nucleus lies in one section, I have drawn the upper- and the 
lower half apart. This offered the advantage, that the gemini lying at 
a low level, could be drawn entirely and were not covered by those of 
a higher level. Some chromatine-elements from the lower half are also 
reproduced in the upper half, but in contour only. This allows one to 
see how the upper half covers the lower one. In all 67 chromatine-ele- 
ments are pictured. The nucleolus caused some difficulty because some 
chromosomes are adpressed to it, so that the total number of chroma- 
tine-elements could not with certainty be determined. Of about 50 the 
bivalent nature is apparent, of the others the bivalency is not entirely 
excluded, of part of them even very probable. Doubtless therefore the 
total number of chromosomes in this nucleus is larger than the sum of 
the haploid numbers of the parents. Nuclei, like the one here pictured, 
occurred very generally in the preparations of these hybrids. They give 
the impression of nuclei with bivalent chromosomes only. It may hap- 
pen however, that the chromosomes of some pairs are not entirely ad- 
pressed, as a consequence of which unpaired chromosomes occur in the 
nuclear plate and in the anaphase just as we have seen this in the case 
of S. officinarum. 
The number of unpaired chromosomes however is here not larger 
than in the case of S. officinarum and it is probable, that they occur 
