196 



SEAWEEDS 



auxospores varies within one genus at least, viz. 

 Cocconeis. 



The Geographical Distribution. Diatoms are dis- 



FIG. 60. -Pelagic Diatoms, a, Chft'toceras necundum : b, rianktoniella Sol; 

 c, Bacteriastruvi variant highly magnified. (After Schutt.) 



tributcd in extraordinary profusion in the sea, in 

 fresh and in brackish waters, and the species found 

 in any of these situations are peculiar to it. The 



