308 Chromosomes in the Spermatogenesis of Anasa Tristis 
chromosomes which divided transversely in the first division are to divide 
transversely also in the second division, but in the light of the early first 
prophases, it seems more reasonable to interpret the elongated form of 
the chromosomes in Photos. 19 to 22 as due to other causes, rather 
than to believe that the line of division so clearly marked out in the 
early stages should be abandoned and the chromosomes divide at right 
angles to it. This would hold true also for those exceptional cases in 
which the eccentric chromosome appears to divide transversely in the 
first spindle. 
Any investigation of the individuality of the chromosomes involves 
a consideration of the theory of the conjugation of the paternal and 
maternal chromosomes and no study of the chromosomes of a special form 
can be even approximately thorough, without an attempt to point out the 
relation in which it stands to this popular theory. As in the case of the 
more general theory of the individuality of the chromosomes it is first 
important to define the kind of evidence one considers necessary to sup- 
port the theory in question. If one is satisfied with the evidence that 
because so many of the spermatogonial chromosomes are duplicates, 
we may safely conclude that all are duplicates and that each bivalent 
of the first spermatocyte is composed of two duplicate univalents, many 
of these resembling the spermatogonial duplicates, then we may feel 
justified in saying that Anasa unqualifiedly supports the theory of 
the conjugation of paternal and maternal chromosomes. But we do 
not feel that such evidence justifies us in claiming that Anasa stands 
for this theory unless we can support it by the further evidence of 
a complete continuity of the chromosomes between the stages of paired 
spermatogonial chromosomes and spermatocyte bivalents. On the con- 
trary, the evidence points rather to a complete disintegration of every 
chromosome unit during this period of the resting spermatocyte and 
we have, therefore, no right to affirm that there is no commingling 
of the chromatin during this stage—that the individuality of each 
chromosome is maintained. 
It seems to us that some reliance can be placed on the preparations 
shown in Plate I, Photos. 1 to 12, where it is clearly demonstrated that 
the individual chromosomes have lost completely their chromosome form 
and in their place we find chromatin granules, a chromatin reticulum, or 
a chromatic skein. It is certainly not unreasonable to believe that at 
this period the substance of the chromosomes may become commingled 
and transformed into the above-mentioned chromatic structures, plainly 
visible under the microscope, and that it finally emerges from this period 
