92 JOSE F. NONIDEZ 
tween the M-chromosomes and the X-chromosome, a fact which 
stands out very clearly during the dissociation of some of the com- 
plexes. The same could be said of figure 83. Here a small por- 
tion of one of the small chromosomes is seen to the left of the 
X-chromosome. The M-chromosome to the right is shorter than 
that to the left, and a break of outline suggests that this inequal- 
ity is also due to the interpolation of the other small chromo- 
some, otherwise apparently lacking. It might be well to em- 
phasize that this peculiarity was discovered some time after the 
figures were drawn, when the intermediate position of the small 
chromosomes in the dissociating complex was definitely estab- 
lished. 
During the pachytene stage the M-chromosomes are approxi- 
mately as thick as the euchromosomes. However, the latter are 
double, as shown by the splitting which appears during the 
short diplotene condition. I think there can be no doubt about 
the univalent character of the M-chromosomes, for if we con- 
sider them as double, their number in the spermatogonia should 
be four instead of two, an open contradiction with the facts. 
Assuming that the M-chromosomes are ordinary chromosomes, 
as indicated by their structure throughout the growth period, I 
thought (14) there was evidence in favor of telosynapsis for the 
euchromosomes. The splitting of the diplotene stage was re- 
garded as the plane of the equational division, which was already 
present even before the first division had taken place. I am more 
inclined at present to admit the existence of parasynapsis, al- 
though there is not conclusive evidence supporting this view. 
If parasynapsis really occur, we cannot fail to recognize that 
the behavior of the M-chromosomes in this respect is entirely 
different from that of the euchromosomes. Furthermore, the 
direct connection of the X-chromosomes and the interpolation 
of the small chromosomes between the latter and the X-chromo- 
some removes the possibility of a normal parasynaptic associa- 
tion, or at least makes it very problematical. 
The importance of the behavior of the M-chromosomes for the 
interpretation of the complex will be discussed elsewhere. 
