SPECIES OF ALGJE. 57 



k. Membrane of spore smooth (/). 



k. " " " punctate (s). 



1. Cells less than twice as long as wide (m). 



1. Cells twice or more " " " " (). 



m. Diameter 22-25^; i-i^ times as long as wide, . subsalsa, 212 



m. " 2 5-33 M; 1-2^ " " " " " . . varians, 212 



m. " 33-40 /*; 1-2 rarely 6 " " " " . . quinina, 215 



w. 48-7 5 //; i-i^ times " " " " . condensata, 215, 



//. Diameter 33^ or more (o). 



n. " less than 33^ (q). 



o. Diameter 33-40/^5 1-2 rarely 6 times as long as wide, quinina, 213 



/. Cells 3-7 times longer than wide; spiral dentate . Lutetiana, 214 

 /. " 2-4 " " " u fusco-atra, 215. 



q. Cells 3-5 times as long as wide (r). 

 q. Cells 2-12 times as long as wide (gg). 



r. Diameter 2 2// or less . . flavescens^ gracilis, 2 1 1 ; communis, 213 

 r. 24ju or more ..... varians, 212; Jurgensii, 213 



s. Diameterof cells 24-27^, 6-12 times longer than wide, punctata, 215 

 /. Spirals 2 (//). 



* " 3 (*) 



/. " 4 M- 



/. " 5 () 



t. " 6 or more (/"). 



^. Diameter of cells 40/4 or less (z'). 



w. " " more than 407^ (w). 



v. Cells 2-4 times as long as wide ....... decimina, 216 



v. " 4-14 "**<< " " ........ elongata, 221 



?#. Cells 1-2 times as long as wide ....... subaqua, 217 



w. " 1.5-2.5 " " " " " .......... dubia, 220 



x. Cells 9o-iooyw in diameter, joints somewhat constricted, 



jugalis, 219 



x. Cells 5o// or less in diameter (y). 

 x. Cells more than 50/1 in diameter (z). 

 y. Cells 7-11 times as long as wide ....... rivularis, 220 



y. " less than 7 times as long as wide . . . dubia, adnata, 217 

 z. Cells 1-2 times as long as wide ....... subaqua, 217 



z. " 2-3 " << ....... orthospira, 218 



s. " 2-5 " ........ neglecta, 226 



2. " 2.5-10 "' " " " " ....... majuscula, 221 



5 



