1911] GATES—CHROMOSOME REDUCTION 339 
The general point of view resulting from the foregoing studies 
and considerations may now be briefly stated. Both the telosyn- 
aptic and the parasynaptic methods of reduction occur, but the 
difference is not of phylogenetic significance, depending rather 
upon the mechanics of nuclear processes. In forms having long 
threadlike chromosomes, the pairing may be expected to take place 
side-by-side and a strepsinema stage is therefore likely to occur, 
while with forms having short stout chromosomes, the pairing is, 
on account of the different spatial relations, more likely to be end- 
to-end, the pachynema segmenting directly into a more or less 
continuous chain of chromosomes. In the same form (for example, 
in Oenothera) the somatic chromosomes may be laterally paired 
in metakinesis, while the heterotypic gemini are at first arranged 
end-to-end, later frequently swinging round so as to lie side-by- 
side. It is probably true, as already pointed out, that the chromo- 
somes in somatic prophases in this genus are also at first arranged 
endwise. This requires further investigation. 
It is also evident that the difference between parasynaptic 
and telosynaptic pairing in meiosis is devoid of hereditary sig- 
nificance, for reasons already stated. Since the chromosomes are 
in homologous pairs from the early divisions of the fertilized egg 
Onward, the need for a synaptic contraction to bring about an 
exchange of particles or influences is imaginary. The synaptic 
Contraction is instead (at least in some forms) in large part an 
appearance, due to an inordinate increase in the karyolymph at 
this time. The main established facts regarding the life cycle 
are that the chromosomes are in homologous pairs throughout 
the Sporophyte, and that the members of the pairs are segregated 
In the heterotypic mitosis. 
I may call attention to the fact that, although reduction con- 
sists simply in segregation of the descendants of homologous 
chromosomes which were first associated as pairs soon after fer- 
tilization and remained so associated throughout the sporophyte 
°F soma, yet the orientation of these bodies in the heterotypic 
metakinesis permits varying distributions of the respective mater- 
