18 ARTHUR BOLLES LER 
at this time show with all the vigour and distinctness with which 
they show at the anaphase, this may be sufficiently accounted 
for by the greater difficulty of observing them in the closely 
collocated moieties of the equatorial chromosomes. But it 
may equally well be that they only attaim their complete 
development at the anaphase. We find, then, that the periaxial 
spirals are only temporary formations. The assertion of Bo n- 
nevie and Vejdovsky that they persist after the telophase 
as rudiments of a new generation of chromosomes is contrary to 
the facts. For we have found that the chromosomes of the 
late telophase are for the most part without periaxial 
spirals and sheath ; and that that which persists and passes 
into the interphase is nothing but the thus simplified a x es of the 
chromosomes. ‘These, on passing into the interphase, frequently 
become coiled into very regular spirals, such as have been de- 
scribed and figured by many observers (for instance, Bonne vie 
for Ascaris and Allium, Vejdovsky for Ascaris 
and other objects, Schneider for Salamandra, and 
myself for Paris quadrifolia); but these do not consist 
of periaxial spirals set free from the shaft of the axis, but of 
the entire axis in a simplified state. The chromonema 
theory 1s a mare’s nest. 
We may nowsumup. There are two types of chromo- 
somes: one (hitherto only found in plants) which is alveo- 
lated from the prophase to the telophase ; and one (hitherto 
only found in animals) which is not alveolated at those stages 
or any other. This last consists (at those stages) of a solid 
basophilous axis, possessing a certain spiral sculpturing of its 
surface, which we have called the periaxial spiral, and enclosed 
in an acidophilous sheath. But this sheath is perhaps common 
to both types ; and if the suggestion thrown out in the note on 
p- 4 should prove correct the periaxial spiral would also be 
common to both. Then the only important difference between 
the two would be that the plant chromosomes have an alveo- 
lated, i. e. more or less hollow, axis, whilst the animal chromo- 
somes have an entirely solid one, 
