BOT.-VOL. I.] WILLIAMS— PASSIFLORA CCERULEA. 197 



do in Larix; indeed, their disappearance before the forma- 

 tion of the multipolar spindle would seem to prove that 

 they have no such function. 



The unbroken network stage in Passiflora (figs, ii and 

 12) is much more striking than in Larix, and the cones are 

 formed directly by the drawing out of this network without 

 a preliminary converging of radial fibers such as Belajeff 

 describes. 



The conversion of a reticulum into spindle-fibers has also 

 been described by Wilson (1895). In his work on the ^gg 

 of the sea-urchin, he shows that the spindle-fibers are differ- 

 entiated out of the Hnin reticulum. 



To point out briefly the differences in the mode of form- 

 ation of the multipolar spindle in Eqtitsetum, Larix, and 

 Passiflora: in Equisetum, the cones are formed solely by 

 the converging of radial fibers and only come into contact 

 with the Hnin network after they have reached their full 

 size ; in Larix, they are formed by the converging of radial 

 fibers, and subsequently increase in size by the pulling out 

 of the network at the places where they are attached to it; 

 in Passiflora, they result from the simple drawing out of the 

 network. 



Summary. 



The cytoplasm of the cell in the spireme stage is com- 

 posed of two separate elements. First, a reticulum stretch- 

 ing from nuclear wall to cell-wall, and, second, a granular 

 substance uniformly distributed in and upon the meshes of 

 the former. When spindle-formation begins the granular 

 substance collects some distance from the cell-wall and 

 forms a dense zone— the granular zone (figs. 11, 12, 13). 



The spindle is formed as follows: The nuclear cavity 

 gradually becomes filled with a Hnin network. The nuclear 

 wall is transformed into a meshwork which connects the 

 Hnin network with the cytoplasmic reticulum, making a sin- 

 gle continuous network which fiUs the entire cell. That 

 portion of the network which Has in the center of the ceH, 



