THE MEIOTIC PHENOMENA IN BLAPS 81 
rence, judging from the slight numerical variation found in the 
secondary spermatocytes. 
The dissociation of the complex usually takes place when the 
already divided euchromosomes are on their way to the poles 
of the spindle. It starts with the loosening of the links which 
hold the chromosomes together, followed by their partial sepa- 
ration; for, in the early anaphase at least, they remain bound to- 
gether by means of connecting fibers (figs. 49 to 51). The X- 
chromosome and that M-chromosome which possesses a fiber 
attachment separate and pass to opposite poles of the spindle, 
while the remaining M-chromosome (which lacks a spindle fiber) 
accompanies the X-chromosome (figs. 49 to 52). In the late 
anaphase, when the euchromosomes become crowded at the poles 
of the spindle, it is still possible to detect the large chromosomes 
outside of the clumped smaller ones and thus to be sure of their 
final distribution. 
The two small chromosomes of the complex are easily detected 
when only fused with the X-chromosome, as they appear as more 
or less conspicuous knobs on the surface of the latter (figs. 49 and 
50); in other cases, however, their recognition is not possible until 
the components of the complex have entirely separated. I was 
at first inclined to admit their absence in such complexes, but, 
fortunately, the presence of a closely graded series of stages in a 
single cyst enabled me to trace their history during the anaphase, 
which has been confirmed by the inspection of many other cells 
in mitosis. 
The study of the complexes undergoing dissociation shows that 
the small chromosomes may be situated between the X-chromo- 
some and the M-chromosomes, and hence they escape detection 
in earlier stages. When lying between the X-chromosome and 
the antagonistic M-chromosome (which passes to the opposite 
pole of the spindle) at the beginning of dissociation, a connecting 
bridge appears between the X-chromosome and the M-chromo- 
some (fig. 54, a); in some cases this bridge is split lengthwise (bd). 
As the separation of the large chromosomes progresses the small 
ones gradually emerge from this connecting tract and finally be- 
come conspicuous, lying either end to end (e) or side by side 
