Igtt] GATES—CHROMOSOME REDUCTION 329 
interpretation assumes an unwarranted amount of “secondary 
fusion” between the chromosomes to form a chain, as indicated, for 
example, in his figs. 23 and 24. It seems to the writer equally 
justifiable to assume that the apparent rarity of a strepsinema 
stage is real, and that usually the chromosomes do not pass through 
such a stage during maturation. This obviates the necessity of 
ding an explanation for an amount of “‘secondary fusion” 
between the ends of the chromosomes, which is not easily accounted 
for. This has always been a serious stumbling-block for those 
who affirm the universality of parasynapsis, in which the pachy- 
nema is followed by a strepsinema stage. 
Let us now inquire what is the exact difference involved between 
the methods of telosynapsis and parasynapsis as described in 
current papers. Telosynapsis involves the folding and looping 
and subsequent segmentation of a single thick thread (pachy- 
nema) which may have previously exhibited a split which closed 
up, to reappear only in the anaphase or telophase of the heterotypic 
Mitosis as a longitudinal split in the components of the heterotypic 
gemini. Parasynapsis involves the lateral pairing of delicate 
threads at a stage earlier than the pachynema, their more or less 
complete fusion to form the pachynema, and their subsequent 
Separation to form the strepsinema stage with paired threads, 
which, by shortening and thickening and (in the cases where a con- 
tinuous pachynema or strepsinema spirem is supposed to be 
formed) transverse segmentation to form chromosome pairs, which 
when first formed are characteristically composed of two long and 
harrow threadlike chromosomes lying side-by-side and more or 
less coiled about each other. Later, by shortening and thicken- 
ing, these chromosomes may, as in Drosera (ROSENBERG 18), 
become short and stout, or as in Lilium they may remain relatively 
long and narrow, even in diakinesis and the following metaphase. 
I think it can be shown upon analysis that the difference 
between these two methods of reduction is far less fundamental 
than has been generally supposed.4 I further believe that the 
* A recent important paper by Miss DicBy (2a) is quite in accord with this point 
of view. Miss Dicpy has made a fresh and careful study of somatic and meiotic 
‘ivisions in Galtonia. She interprets the paired threads in early prophase of the 
