644 Wisconsin Academy of Sciences, Arts, and Letters. 
definite arrangement of the parental chromosomes and it seems 
probable that at some period during the diploid generation 
there is a distribution of homologous chromosomes to form 
pairs. 
It is at the time of the formation of the spores at the close 
of the diploid generation that the chromosomes seem to come 
into close and intimate contact but. no satisfactory evidence is 
yet available as to when or how the homologous chromosomes 
from the two parents have come into such relations that the 
synaptic pairing becomes possible. 
The last typical divisions preceding synapsis in Smilacina, as 
described above, differ in no way from ordinary somatic divi¬ 
sions. There is no evidence that any preparation for reduction 
occurs immediately preceding the heterotypic division but it 
seems clear that there is an abrupt change from an ordinary 
division immediately preceding synapsis to the heterotypic divi¬ 
sion immediately following it. If there has been a pairing of 
homologous paternal and maternal chromosomes previous to 
synapsis it must have taken place at a period previous to the 
nuclear divisions in the young anther. 
The conduct of the nuclei in the diploid generation of the 
rusts, which do not fuse until immediately before reduction in¬ 
dicates that here the pairing of the homologous parental chromo¬ 
somes must take place after the last pre-reductional division, 
immediately after fusion and immediately preceding reduction. 
The work of Ruckert, Hacker, Mioenkhaus as well as the 
above mentioned authors on the Gymnosperms indicates that 
the association of homologous parental chromosomes does not in 
the forms studied take place immediately upon the fusion of the 
gametes but that the chromosomes of the twt> parents may re¬ 
main distinct for several cell generations, though 1 finally be¬ 
coming merged into one homogeneous group. Still the pres¬ 
ence of paired chromosomes in somatic nuclei as reported in 
Funkia, Galtonia, Yucca and other plants suggests that there 
may be a relatively early pairing of homologous chromosomes. 
These phenomena may indicate that though the parental 
