1900] ACHROMATIC SPINDLE OF OSMUNDA 373 
frst parallel to one another, come to lie at an angle of 60°. 
hhis results in placing the four daughter nuclei equidistant from 
me another in the tetrahedral arrangement which is character- 
stic of fern spores. Whether the rotation is brought about by 
the action of the secondary fibers, or by some other influence 
acting on the nuclei, could not be determined. In fig. 27 two 
primary spindles are shown, and some of the seconday fibers not 
jet united by their extremities. In jig. 22 are one primary 
spindle (that on the left side) and two secondary ; the axes of 
the other three spindles would make angles of 60° with these 
or with the plane of the paper. 
The disappearance of the spindle has been followed with 
stat care in order to discover, if possible, in what manner the 
kinoplasm is metamorphosed into ordinary cytoplasm. It was 
‘ound that the middle fibers of all the spindles are the first to 
disintegrate, the material being used up in part to build the cell 
Mate. After the spindles are no longer distinguishable, a con- 
‘derable amount of granular or amorphous matter remains on 
the inner side of each nucleus (jig. 24); finally this disappears 
and the cytoplasm assumes a reticulate structure throughout 
lis 25). All attempts to identify the granules of kinoplasm 
with microsomata, or the fibrous matter of the spindle with the 
Flop lasmic reticulations, were unsuccessful. The fibers of the 
‘pindle are composed of modified cytoplasm, which in the 
ansformation loses its characteristic structure and becomes 
“structureless in appearance, then granular, then fibrous, and 
‘ning to its normal condition reverses these steps. 
SUMMARY. ; 
The achromatic spindle originates wholly from cytoplasmic 
Materia] (kinoplasm) which accumulates about the nucleus in 
*YMapsis or spirem stage in the form of an indefinitely gran- 
mass of stainable matter. n- 
: The Kinoplasm becomes distinctly granular; then se Aig ‘ 
é ‘range themselves into short rows concentric wa 
Q ssed in 
Uclear membrane ; finally the rows of granules sr aR 
