x1] STONEWORTS, AND PEPPERWORTS. 16s 
liar hygrometric properties. If placed upon a glass- 
slide, breathed upon, and then placed under the 
microscope, these elaters will be seen to undergo 
some curious movements. ‘Some will be quite 
closed up, the elaters being so closely applied to the 
spores as to be scarcely distinguishable; others, again, 
will be seen gradually unfolding the filaments, and a 
few may be observed to move with a sudden start, as 
it were, from the contracted state of the elaters to 
that of full expansion. The ultimate cause of this 
movement is quite unknown. That it depends upon 
the amount of moisture with which the spores are 
surrounded there can be no doubt. Most probably 
it takes place by the contraction and expansion of 
the cells of which the elaters are composed, under the 
varying influence of the moisture contained in the air. 
The phenomenon is a very curious one, and should 
by all means be seen by every one who possesses a 
microscope” (H. W. S. in “Science Gossip,” 1878). 
Fic. 117. 
Fic. 119. 
The spore on germinating gives rise to a prothallus 
similar to that of ferns, .and in the same manner 
bears antheridia and archegonta, which ultimately 
develop a true bud, and from this the new plant 
springs. 
