Spindle in Vegetable Cells of Higher Plants 453 



Hierauf erst werden gleichzeitig an zwei diametral -entgegenste- 

 henden Punkten der Kernoberflache, ihr kappenformig aufsitzend, 

 kinoplasmatische Ansammlungen kenntlich, * * * Dis Fasern con- 

 vergiren gewohnlich alle nach einem Punkt, dem Pol der Kappe ; 

 die Spindel-Anlage ist als dann worklich bipolar/' 



According to Shaffner ('98) in his paper on karyokinesis in root 

 tips of Allium cepa, " The division begins with the separation 

 of the centrospheres, and when these have moved apart nearly 

 180 the incept (anlage) of the achromatic spindle appears, form- 

 ing two dome-shaped projections on opposite sides of the nucleus, 

 at the summits of which centrospheres are situated, forming the 

 poles around which are cytoplasmic radiations." 



"These centrospheres gradually extend outwards, drawing 

 the spindle into a sharp pointed bipolar structure." " The incept 

 of the spindle is very sharply differentiated from the surrounding 

 cytoplasm and the space between it and the nuclear membrane 



appears very clear and transparent, like the achromatin of the 

 nucleus." 



The mantle fibers he regards as streams of cytoplasm which 

 have nothing to do directly with the formation of the spindle. 



In a study of nuclear division in the root-tip of Allium cepa 9 

 Vicia faba and Erythroniutn Amcricanum my observations have 

 shown that in many cases, at least, certain very early stages in the 

 development of the spindle have been overlooked by the three ob- 

 servers just cited. 



The material for this study was prepared according to the 

 method used by Mottier ('97) in his studies of Lilium. 



In the earliest stages observed by me the fibers which take 

 part in the formation of the spindle are comparatively few, and dif- 

 ficult to differentiate from the remaining cytoplasm. 



In some cases at least the spindle anlage takes its origin in a 

 delicate kinoplasmic weft surrounding the nucleus, rather than 

 within a clear space or court formed about the nucleus. Figs. 1 

 and 2 represent two very early stages. In Fig. I the kinoplasmic 

 fibers present form a delicate weft about the nucleus. In Fig. 2 

 the weft is more pronounced and it is seen to retreat from the nu- 

 cleus at two opposite points forming the cap-like spaces or courts 

 described by Nemec. In Fig. 2 it is not assumed that the fibers 



