PLATE XIX. 



FIGS. PAGE 



1-2. Closterium siymoidenm Lagerh. & Nordst. x 



170 . 153 

 3-5. Cl. sigmoideum forma major West & G. S. 



West, x 170. . . 153 



6-8. Cl. Siliqua West & G. S. West, x 520 . 154 

 9-11. CL perac<T<>,\/ini Gay. 9 and 10, x 400; 11, 



x 400 (after Gay) . .154 



12-13. Cl.peracerosumvar.elegansGr.S.West. x 520 155 



14. Cl. littorale Gay. x 400 (after Gay) . 155 



15-18. CL t HIII nl inn Johnson. x 520 156 



