STRUCTURE OF CERTAIN CHROMOSOMES 15 
a continual displacement of the direction of the axes, making it 
extremely difficult to follow them accurately for more than very 
short distances, and thus making it next to impossible to dis- 
tinguish the periaxial spirals running across them. Still, at 
this stage, it can be inferred with certainty that these exist at 
least to some extent ; for indubitable lateral processes can be 
made out in some places ; and the sheath can be observed with 
certainty in favourable places, as shown in figs. 39 to 45 (in some 
places of these, where not sufficiently evident in the drawings, 
IT have marked it with a cross). 
When the expansion of the clump has attained its greatest 
extent, we have the telophasic ring, figs. 48 to 51, 
and others. The chromosome axes are here about as distinct 
as before; but the periaxial spirals, lateral processes, and 
sheath seem to be waning. ‘The spirals can no longer be 
seen as lines running across the shaft ; and the lateral pro- 
cesses can only be distinguished from the interchromosomal 
trabeculae here and there. But this does not necessarily imply 
that they have diminished in number. For at this stage the 
chromosomes have elongated considerably ; and since by their 
elongation the periaxial spirals and their processes must be 
pulled away from one another, we naturally find far fewer pro- 
cesses than before on any given length of an axis. But this is 
probably not all that happens. The chromosome of the 
anaphase and early polar clump is a very tightly twisted 
cylinder ; and there is nothing forced in the supposition that 
the spirals on its surface, and their lateral processes, are mere 
effects of the torsion it has undergone. And it appears natural 
that as the axis elongates at the telophase, it should unt wist; 
and that m consequence of this untwisting the spirals come to 
subside into the shaft, carrying their processes down with them. 
Not that the substance of the spirals and processes degenerates 
or dissolves ; but that it undergoes a change of configuration : 
as when [ extend a finger, wrinkles start up on its surface ; 
and when I flex it these wrinkles are smoothed down. But be 
this as it may, it is certain that in the telophase the periaxial 
spirals and processes begin to wane out of sight, till in the 
