FREE CELL-FORMATION. 



99 



or compartments of the chambers ah-eady 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.— Fniiki'a cordata. A transverse 

 section of a young pollen sac before tlie isolation of the 

 mother-cells (j;«); cp the epithelium (Tapetum) clothing 

 the loculus ; 7u wall of the pollen sac. ß loculus 

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

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

 following figs.) 



Fig. loi.—Fiiiiiia ovnta. Development of pollen 

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

 water and burst : 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 cell of Fuiikia ovala. 

 The ctternally projecting thickenings are still small (in 

 C they are larger) and arranged as lines connected into a 



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 apparently very 

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



