496 ARTHUR BOLLES LEE. 
Fig. 8. A dark axial line appears in the hyaloplasma. .The arrows show 
the sinuous diagonal line along which the segments will split. 
Fig. 9. The segments have split, and the resulting moieties have wheeled 
half round in order to place themselves on either side of the equator. 
Fig. 10. The moieties have completed their half turn, have thickened by 
contracting, and are about to start for the poles of the spindle. 
Fic. 11.—This and the following figure are mother-cellsfrom the testis of 
Aidipoda cerulea. 
In Fig. 11 the segments of the mother-star have arranged ‘themselves in 
two lateral groups, and the spindle has begun to flatten. Two asters. 
Fig. 12. The two lateral groups have further separated in the equatorial 
plane. The spindle, now fully formed, is stretched out in the equatorial 
plane, as testified by one aster which still remains to indicate the 
organic axis of the cell. Note that the spindle-fibrils are continuous 
at the poles, the place at the poles being indicated by the one re- 
maining aster. 
Fie. 13.—Mother-cell from the testis of Crangon cataphractus. The 
two daughter-stars, seen a little obliquely, are composed of U-shaped elements 
arranged regularly round the poles, with the bend of the U’s looking in the 
direction of the axis, and one limb of the U’s directed inwards the other 
‘outwards. These limbs are now beginning to curve inwards towards the axis, 
and will continue to do so till they take hands with their right and left vis-a- 
vis. e. “Nebenkern” or accessory corpuscie, playing no part in cell division. 
pe. Cell-plate, complete. 
Fic. 14.—Schema, showing how the chromatic segments of the preceding 
figure unite with their vis-a-vis. ¢. External limb. 7¢. Internal limb. 
Fig. 15.—This and the following figure are mother-cells from the testis of 
Harpalus griseus. 
Fig. 15. The skein-form or convolution of the first prophase is arranging 
itself in long loops parallel to the direction of the spindle. Spindle 
and asters visible, though not complete. Note that the nuclear mem- 
brane is still intact. 
Fig. 16.—More advanced stage of this process. The chromatic loops have 
taken on a perfectly regular arrangement parallel to the spindle, and 
have thinned out and broken towards the poles. The segments thus 
obtained will now contract and thicken, and without further change 
of place form a mother-star like that of Fig. 6 or Fig. 18. Note that 
the fibrils of the asters are continuous, at least in many instances, at 
the equator. 
Fic. 17.—Nucleus of a testicular cell of Stenobothrus. Mother-star 
formed iu the usual way by grouping of the scattered segments, resulting from 
the transverse fission of the skein. Nuclear membrane perfectly intact, en- 
closing a spindle, not indeed fully formed, yet very evident. Drawn from a 
