McAllister—Cytology and Embryology. 
639 
with those of the heterotypic telophases. From the fact that 
large masses remain intact through the resting condition,—that 
the homoeotypie chromosomes are formed very quickly without 
the intervention of a spirem stage and from their general shape, 
size and position it seems reasonable to conclude that they are 
the same. 
As these homoeotypie chromosomes become aggregated in the 
equatorial plate they have the general elongated form of chromo¬ 
somes of typical mitoses and in the metaphases the two halves 
are separated one part going to each pole. 
DISCUSSIOK 
The observations described above for Smilacina racemosa 
point strongly to the conclusion that in the early prophases of 
the first reduction division a longitudinal pairing of leptonema 
spirems occurs. The thin pre-synaptic chromatin strands fre¬ 
quently appear paired. The strands increase in thickness as 
the nucleus is entering into synapsis as would be the case if 
there were a lateral approximation of two thin spirems. Tan¬ 
gential sections of the synaptic knot frequently show that the 
spirem is here double. The simplest interpretation of these 
facts is that there has been a side by side pairing of thin 
chromatin strands during these early prophases. 
These evidences are strongly supported by other phenomena 
of the later prophases. It seems clear: (1) that the longitudi¬ 
nal split of the later prophases does not close up but persists 
until the halves are finally separated: (2) that the transverse 
segmentation is not exclusively central, but in most cases at least, 
occurs near the periphery; (3) that the shortening and thick¬ 
ening of the spirem segments after the transverse segmentation, 
is gradual and not the sudden shortening and thickening that 
would necessarily result from the lateral approximation of the 
two limbs of a loop composed of two chromosomes attached end 
to end. As far as I am aware no investigator of the reduction 
divisions has called attention to any such sudden shortening and 
