470 Chromosomes of Anasa Tristis and Anax Junius 
and 50, 07b, which show only two large chromosomes, while in each case 
two other chromosomes are lying with their ends in contact and at an 
angle to each other, as if they might well be portions of the large bent 
chromosome which has become partially severed, but which is seen intact 
in sections. 
Side views of the spermatogonial spindles clearly prove that all of the 
chromosomes at metaphase lie in a flat plate and preclude the possibility, 
as Wilson has pointed out, that some of the chromosomes may be outside 
the plate at this time, and hence fail to be included in a transverse sec- 
tion. The spermatogonial groups, therefore, show in this material not 
only the same number but precisely the same form-relations of the 
chromosomes as described and figured by Wilson, and afford a detailed 
confirmation of his results. 
Our sections, furthermore, lend strong support to Wilson’s view that 
the “ chromosome-nucleolus ” of the growth-period is the persistent odd 
chromosome of the spermatogonia, and not merely a chromatin nucleolus, 
as maintained by Foot and Strobell. They also furnish the most indis- 
putable evidence of the asymmetrical distribution of the heterotropic 
chromosome at the second division. There is not the faintest indication 
that it is merely a “ lagging chromosome” which divides at a late period 
of the anaphase, as is believed to be the case by the latter observers, but, 
on the contrary, every stage in its passage without division to one pole 
of the spindle can be followed. If any doubt as to this fact should remain 
from an examination of side views, two of which are given in. Fig. 1, G 
and H, it is at once removed by seeing sections of the daughter plates of 
the same spindle which show ten chromosomes in one and eleven in the 
other, as figured by Wilson. J and J of Fig. 1 represent polar views of 
the daughter groups of the second division, the former lacking, the latter 
including the odd chromosome. These two groups belong to the same 
spindle and were drawn from the same section at different focuses, as 
one was lying immediately above the other in the same cell. The odd 
chromosome in J is easily recognized at h; it lies just below the others, 
while the remaining chromosomes in the two groups correspond exactly 
in size and relative position. It by no means always lies on the periphery 
of the group, but may be found in any position. The designation 
“eccentric,” which Miss Foot and Miss Strobell apply to this chromo- 
some is, therefore, a misnomer, for its position outside of the group at 
the second division—an occurrence upon which they lay much stress—is 
far from being a constant one. 
Several such instances as that figured in J and J have been found, and 
