CHROMOSOMES OF PERLA Byles 
division. The fact that these two chromosomes are of totally 
different sizes and shapes, and that the coupling takes place 
most regularly between these two, seems to signify much, be- 
cause these afford a complete demonstration of the occurrence 
of synapsis, in so far as these two chromosomes are concerned. 
Although this does not show that a similar process must take 
place in other pairs of chromosomes, it does, nevertheless, add 
more to the probability of the general occurrence of synapsis. 
However, it is evident that the case of the ordinary chromosomes 
must be established through their direct study, for it is not without 
reason to suspect that some differences may be found in the 
process from that seen in the case of the accessory chromosomes. 
Suggested modes of synapsis 
In the case of Perla, facts show for certain of the chromosomes, 
and hence with probability for all the other chromosomes, that 
synapsis does take place in the maturation of the germ cells. 
Before entering into the closer examination of the critical stages 
where the process of synapsis may possibly be involved, it would 
be well to review briefly the interpretations of some of the pre- 
vious authors. 
Vejdowsky (07) is of the opinion that the chromosomes in 
normal number conjugate parasynaptically and fuse completely. 
The mixochromosomes (haploid number) thus produced split 
longitudinally at both divisions. 
Bonnevie (07, ’08a, ’08 b, 711) considers that the diploid 
chromosomes conjugate parasynaptically, and although the con- 
jugants fuse completely in the maturation period, during which 
they do not separate, they ultimately become distinct. 
According to Henking (90-92) and Korschelt (95), the 
spireme segments into the diploid number of chromosomes, all 
of which undergo longitudinal splitting and remain separate until 
the metaphase, when they conjugate and appear again in the 
haploid number. The conjugants may separate at the first 
division. Goldschmidt (08a, ’O8b) is of the same opinion, 
but he maintains that the separation of the conjugants takes 
place at the second division. 
JOURNAL OF MORPHOLOGY, VOL. 32, NO. 3 
