196 SEAWEEDS 
auxospores Varies within one genus at least, viz. 
Cocconets. 
The Geographical Distribution—Diatoms are dis- 
Fie. 60.-—Pelagie Diatoms. a, Chirtoceras secundum : b, Planktoniella Sol ; 
ce, Bacteriastrwin varians highly magnified. (After Schutt.) 
tributed 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 
