192 ROMANCE OF LOW LIFE AMONGST PLANTS. 



or plates, being composed of silex or flint, are practi- 

 cally indestructible by fire, acids, or weather, although, 

 being brittle as glass, they may easily be broken by 

 force, and hence are often met with in fragments or 

 in an imperfect condition. From these skeletons 

 nothing could be determined of the structure and life 



Fig. -ii-— Amphitetras ornaia, from Algoa Bay guano. 



of the original organisms, but this can all be supple- 

 mented from the study of living plants, so that we 

 can determine their place in nature, to which end we 

 submit the following observations. They are essen- 

 tially aquatic plants, or algae, and, as one author 

 observes, " I suppose there is scarcely a single piece 

 of water anywhere which does not contain at least 

 some individuals of the commoner species. They 

 are to be found alike in the lake that crowns the 

 mountain-top and the swamps and peat-beds which 

 fill the lowest valley ; in the watercourse employed 



