492 ARTHUR BOLLES LEE. 
and regularisation of the fibrils of the reticulum of the karyo- 
plasma. They form a continuous, uninterrupted system; that 
is to say, they are not interrupted at the equator (as held by 
van Beneden, who describes the spindle as formed by two 
cones approximated by théir bases); and they are not inter- 
rupted at the poles, but course entirely round the spindle. 
This may be directly observed in those nuclei in which, as in 
the case of Gidipoda alluded to above, the daughter-stars are 
situated on the equator, leaving the poles free for observation 
(fig. 12). 
The Asters.—Just as the spindle is formed by a modification 
of the karyoplasmic reticulum, so the asters are formed by a 
perfectly similar modification of the cytoplasmic reticulum. 
Their rays are true fibrils of plastin, and do not merely consist 
of aligned cytoplasmic granules. Their formation out of the 
cytoplasmic reticulum has been directly observed by Carnoy, 
and is figured by him in many places, e. g. figs. 83, 213a, 301 
to 304, and 309 of the Cytodiérése.” The degree of develop- 
ment to which the asters may attain is extremely variable. In 
fully-developed asters it may be seen, especially by the help of 
digestion, that they form a continuous system; that is to say, 
the ray-fibrils are continuous at the equator (fig. 16). The 
asters then form as it were a cytoplasmic spindle, enveloping, 
but not continuous with, the nuclear spindle. 
Polar corpuscles (cp., fig. 18) are found in all groups of 
Arthropods, but are not constant, and except in Myriapoda 
and Crustacea are decidedly rare. They appear to have an 
almost liquid consistence, and to be merely transitory modifi- 
cations of the cytoplasmic enchylema. They appear to play 
no part of any importance in the processes of cell division. 
Separation of the Daughter-Nucleii—On the dissolution of the 
nuclear membrane the cytoplasmic enchylema rushes into the 
nucleus and mingles with the karyoplasma. The spindle 
elongates, and the daughter-stars are carried out into a more 
or less remote region of the cell-body. Here the new mem- 
brane is formed around them, enclosing a portion of cytoplasm, 
which henceforth becomes karyoplasm, and so much of the 
