THE HIGHER CUYPTOGAMIA. 167 



these processes, and at last that nucleus disappears alto- 

 gether. 



A spore is formed round each of the four secondary 

 nuclei. The four spores do not nearly fill the mother- cell. 

 A viscid fluid jelly fills the space between them (PL XXII, 

 figs. 20, 21). 



A layer of similar jelly is previously visible, forming 

 the innermost layer of the membrane of the mother-cell ; a 

 bright space is formed between the firm lamella of the 

 membrane and the boundary of the cell-contents (PL XXII, 

 figs. 17, 19). 



The first stages of development of the spore-mother- cell 

 of Funaria hygrometrica resemble those of Gymnostomum 

 pyriforme. Two secondary nuclei are formed outside the 

 primary nucleus of the cell in the middle of an accumula- 

 tion of granular mucilage (PL XIX, fig. 12). After- 

 wards four nuclei appear in the place of the two (PL XIX, 

 fig. 14). The primary nucleus, which has become paler, now 

 disappears. Suddenly the mother-cell divides into four 

 parts of the form of a tetrahedron with a convex basal surface. 

 This division is produced by six septa passing through 

 each two of the four secondary nuclei. These four divi- 

 sions constitute the special mother-cells, which in this 

 genus have firm rigid walls, which at first are very thin 

 (PL XIX, fig. 15). After the walls of these special- 

 mother-cells have become considerably thickened by the 

 deposition of gelatinous layers, a spore is produced in 

 each of them, which, at its first appearance, entirely fills 

 the mother-cell (PL XIX, fig. 16). 



The formation of the spores of Funaria more nearly 

 resembles that of the pollen of phaenogamous plants, than 

 the spore-development of Phascum, the similar process in 

 Eucalypta, and that in Gymnostomum pyriforme. The 

 material differences in the process of development of the 

 spore-mother- cells in plants which are in other respects 

 so closely allied, may, without hesitation, be considered 

 as an indication of the fact, that the greater or less degree 

 of firmness of the walls of the special mother-cells is 

 an unimportant circumstance. The essential phenomenon 

 in the formation of four spores or pollen-cells in the 



