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M. G. Sykes 
gradually to be separating from one another, any constancy in the 
number found together could not be expected. The facts observed 
seem to some extent to Support the view that the reduced number 
of chromosomes is primarily less than twenty-four and that the 
larger number actually observed is due to fragmentation of some of 
the members of the chromosome series. 
VII. Origin of multipolar spindle. It is unnecessary to 
describe this well known stage at any length liere, and it will be 
sufficient to say that the long chromosomes, which are now loop- 
shaped and rnuch contracted, are attached to the spindle fibres by 
the middle of the loop and that in each side of the loop the longi- 
tudinal fission is still clearly visible, (Figs. 50. 51. PI. IX.); it is also 
distinct in the shorter chromosomes, which are attached to the spindle 
in various ways. 
VIII. Metaphases. The large chromosomes are generally found 
on the periphery of the equatorial plate 1 ); it is far easier to study 
their division in cases where they are seen in face, not side, view. 
This division takes place along the line of the fission already re- 
ferred to, which corresponds to the line of fusion in the original 
double spireme; each loop thus splits longitudinally along its whole 
length and gives rise to two thinner loops, (Text Fig. III', Fig. 52. 
PI. IX.); cases of division across the bend of a loop were never found. 
Miyake 2 ) describes and figures long chromosomes attached by their 
ends, and States that the looped appearance of each double chromo- 
some is due to the wide divergence of the origiually closely approxi- 
mated halves, which separate as two rods in metaphase, (Text Fig. 
II, III). But in my preparatiou these halves clearly showed a longi- 
tudinal fission, which it has been shown can be traced throughout 
all the stages from the double spireme. The Separation, which now 
occurs, takes place along the line of this fission, as shewn in Figs 52 
& 53, PI. IX., and also in Figs 54b, c. ; in Fig. 54a. the split is also 
visible, but Separation has not yet occurred. Miyake’s figures appear 
to have been drawu from preparations which did not clearly show 
a differentiation into chromatin and liniu, and this may have tended 
to obscure the split which I should have expected to see running 
all round the chromosomes, in such figures as 125 PI. V. and 133. 
PI. V. of his paper, or Strasburger’s Fig. 74. PI. II. 3 ). In cases 
Miyake. 1906. p. 108. 
21 Miyake. 1906. pp. 108. 109 & Figs. 125-133. PI. V. 
3 ) Strasburger. 1900 . 
