522 CANNON: STUDIES IN PLANT HysrRIDs: 
pairs are united in this manner a continuous spireme of single 
chromosomes united end to end would be the result. The results 
of my observations upon this point were somewhat contradictory, 
and this may have been owing to the possibility that not all of the 
nuclei studied were undergoing the last sporogenous division, and 
that the pairing of the chromosomes and the form of telophase fol- 
lowing are, in the pea, peculiar to the presynaptic nuclear division. 
I hope at another time to give a more complete account of this 
division. 
When I observed the association of chromosomes as above de- 
scribed I supposed that it was merely from chance, which indeed 
may yet prove to be the case, and not the usual and normal occur- 
rence in such cells, because it surely is not at all likely that so no- 
ticeable a thing could for any length of time escape the eyes of 
trained cytologists. The better to reinforce the correctness of my 
observation, or to prove it false as the case might be, I studied the 
mitoses in the nuclei of somatic cells. Asa rule, there is no indica- 
tion. whatever in the somatic nuclei of peas of the association of the 
chromosomes in twos, but in one nucleus an appearance recalling 
the pairing was observed. In this case a closer examination 
showed that the association did not include all of the chromo- 
somes and was very evidently one of chance merely; so that it 
seems to me that the association of the chromosomes in pairs in 
the last sporogenous division in Fillbasket does not find a coun- 
terpart in any somatic cells and is not the result of chance. 
FILLBASKET x DEBARBIEUX 
In studying the sporogeny of the hybrid Fillbasket x Debar- 
bieux my aim has been rather to notice departures from the “ nor- 
mal,” and by it to discover if possible the structural causes of the 
remarkable “ splitting” of the Mendelian hybrids, than to examine 
critically and minutely the several nuclear divisions for themselves. 
Accordingly I have observed the behavior of the chromosomes 
more especially in the two maturation mitoses, in the first division 
of the microspore and in the last division of the sporogenous cells. 
The sporogenous cells of the hybrids were rather easily dis- 
tinguished even in young anthers because of their position and by 
the greater density of the cytoplasm, although it should be said 
