CHAP. IV.] ALG^. 473 



they form a thick green slime, by adhering toge- 

 ther on the surface of ditches and cisterns, and 

 in short, wherever there is stagnant water ex- 

 posed to the open air. The disjointed Algae 

 are generally found among the Confervae ; but 

 they are so small, and insignificant in appear- 

 ance, as, in most cases, entirely to escape notice. 



