FREE CELL-FORMATION. 



99 



or compartments of the chambers already present; the new cells appear rather 

 from the very beginning as more or less rounded, independent bodies, isolated from 

 the sister-cells. 



This difference is especially conspicuous where a large number of rounded 

 daughter-cells are formed inside a mother-cell, in such a manner that a portion 



Figs. 99 and 100. — Funkia cordata. A transverse 

 section of a young pollen sac before the isolation of the 

 mother-cells (ivt\ ; ep the epithelium (Tapetum) clothing 

 the loculus; w wall of the pollen sac. B loculiis 

 after isolation of the mother-cells (jot); ep remains 

 of Tapetum (X 550. For further development cf. the 

 following figs.) • 



FIG. iQx,— Funkia ovata. Development of pollen 

 (X 550) yil. The wall of the daughter-cell has absorbed 

 water and buret : the protoplasmic body forces itself out 

 through the fissure, and lies in front of it rounded off as a 

 sphere. 



FIG. 102.— S a young pollen ceU of Funkia ovata. 

 The externally projecting thickenings are still small fm 

 C they are lai^er) and arranged as lines connected into a 

 network. 



of the existing protoplasm of the mother-cell remains unemployed, as in Fig. 97. 

 This mode of cell-formation has long been distinguished from the cell-division 

 previously described as an essentially different process, as free cell-formation: more 

 recent researches have shown, however, that between these apparenUy very 

 different modes of ceU-formation the most various intermediate stages occur, which 



H 2 



