62 University of California Piihlicniions in Zoology [Vol.22 



Gj'rosignia speiu'erii (W. Sm) CI. 



Honioeoi'lailia (Nitzschia) aeieularis. 



Hoinoeocladia amphioxys. 



Homoeoeladie obtusa. 



Homoeoeladia sigma. 



Hoinoeocladia spectabilis. 



Homoeoeladia tryblionella. 



Melosira granulata (Ehr) Balfs. 



Melosira crenulata Ehr. 



Melosira distans. Kiitz. 



Melosira varians Ag. 



Navicula ambigua. 



Navicula borealis. 



Navicula eryptocephala Klitz. 



Navicula iridis. 



Navicula fulva. 



Na^-icula laneeolata Kiitz. 



Navicula parva (Ehr). 



Navicula pupula Kiitz. 



Navicula pygmaea. 



Navicula rhynchocephala Kiitz. 



Navicula viridis (Nitz) Kiitz. 



Nitzschia vermicularis Kiitz. 



Odontidium elongatum (Ag) Kuntze. 



Sphinctoeystis librilis. 



Stauroneis anceps. 



Stauroneis phoenicenteron. 



Surirella biseriata. 



Surirella ovalis. 



Surirella robusta. 



Surirella spiralis. 



Synedra acus Kiitz. 



Synedra capitata. 



Synedra radians Kutz. 



Synedra ulna Ehr. 



Tabellaria fenestrata Kutz. 



Conjtigatae 



station I Station II Station III Daily Hourly 

 Number of forms listed.... 10 15 13 5 5 

 Average number of indi- 

 viduals per cubic meter 121,65.3 3.31,687 420,463 26,827 931,948 



The representation for this group is mainly desmid but there 

 were a few filamentous forms such as Spirogyra included occasionally. 

 These latter occurred in such small quantities, however, that they 

 had no appreciable volumetric effect and the count serves to show 

 their relative importance quite clearly. Including one form of 

 Spirogyra there are seven species of Conjugatae listed here which 

 will be given separate discussion. Even among the desmids the num- 

 ber of individuals was not great. 



