5 lo Farmer . — On Spore- Formation and 
the £ microcentrum ’ does not really represent stages in the 
disintegration of the original centrosome. The researches of 
Moore on Branchipus 1 are of interest in this connexion. 
During the earlier phases in the karyokinesis in the sperma- 
tocytes of this crustacean, granules of a fairly large size (the 
pseudosomes of Moore) are distributed through the proto- 
plasm. They are connected together by cytoplasmic fila- 
ments so as to form a sort of net-work, but are clearly visible 
as separate particles during the earlier period in the existence 
of the achromatic spindle. Finally, they fuse up to form one 
gigantic ‘centrosome,’ and the spindle becomes henceforth 
normally bipolar. It would seem as if these separate particles 
were at first sufficient to start a number of centres of forces 
in the cell, but that these gradually drew together, and 
finally after the pseudosomes had been forced to coalesce, 
a single kinetic centre became a possibility at each end of 
the cell. The same phenomenon of multipolar spindles has 
been observed by several investigators 2 in the early stages 
of nuclear division in Lilies and other plants, though these 
usually pass over into the normal bipolar type at a subsequent 
period. Still any large mass in the vicinity of the spindle may 
serve to disturb the uniformity of the figure, as I have elsewhere 
described in Lilium Martagon ' 6 . These considerations, then, 
seem to confirm the suggestion that the quadripolar spindles 
of these Hepaticae are really only the result of the special con- 
ditions imposed by the configuration of the spore-mother-cell. 
As regards the change which takes place within the nucleus, 
the chromosomes and the nucleolus have long attracted special 
attention. To the latter body indeed almost every conceivable 
function has been attributed. The reason for this is to be 
sought in the extraordinary difference in behaviour which 
the nucleoli of different nuclei exhibit during karyokinesis. 
1 Some points in the Origin of the Reproductive Elements in Apus and 
Branchipus. Quart. Journ. of Micr. Sci., Vol. xxxv. 
2 Belajeff, Zur Kentniss d. Karyokinese b. d. Pflanzen. Flora, Erganzungsbd. 
z. Jahrg. 1894. 
3 Ueber Kerntheilung in Lilium-Antheren, besonders in Bezug auf die Centro- 
somenfrage. Flora, 1895. 
