MVSCI.—BR Y I NEAR. 



187 



quite different to the origin and structure of the true peristome of other genera. In these, 

 with the exception of the Polytrichaceac, neither the teeth nor the cilia consist of celkilar 

 tissue, but only of thickened hardened portions of the walls of a layer of cells which is 



Fig. 145. Fniinri'a hyg}-o»ietrica. Portion of longitudinal 

 ection of an immature theca. Highly magnified, see the text. 



filiformc. A Longitu- 

 after Lantzius-Beninga. 

 B transverse section magn about 5 times ; nu wall of 

 the theca, cu the operculum, c c the columella, / the 

 peristome, fp the epipliragm, a a the annulus, i i the 

 air-spaces traversed by alga-like cellular filaments, 

 s spore-sac containing the primary mother cells, st 

 the seta, the upper part of which forms the apophysis 

 ap. A magn. 15 times. 



Fig. 146. Ftinaria hygrom. 

 ection through the lid (see the t 



. Portion of transverse 

 Highly magnified. 



separated by a few layers of thin-walled cells from the epidermis which forms the lid ; 

 these cells and the thin parts of the layer which supplies the teeth are torn up and dis- 

 appear when the operculum is thrown off, but the thickened portions of the walls remain 

 behind. 



