62 University of California Publications in Zoology [ VoL - 22 



Gyrosigma spencerii (W. Sm) CI. 



Homoeocladia (Nitzschia) acicularis. 



Homoeocladia amphioxys. 



Homoeocladie obtusa. 



Homoeoeladia sigma. 



Homoeocladia speetabilis. 



Homoeoeladia tryblionella. 



Melosira granulata (Ehr) Ralfs. 



Melosira crenulata Ehr. 



Melosira distans. Kiitz. 



Melosira varians Ag. 



Navicula ambigua. 



Navicula borealis. 



Navieula erj'ptocephala Kiitz. 



Navicula iridis. 



Navicula fulva. 



Navicula lanceolata Kiitz. 



Navicula parva (Ehr). 



Navicula pupula Kiitz. 



Navieula pygmaea, 



Navicula rhynchocephala Kiitz. 



Navicula viridis (Nitz) Kiitz. 



Nitzsehia vermicularis Kiitz. 



Odontidium elongatum (Ag) Kuntze. 



Sphinctocystis librilis. 



Stauroneis aneeps. 



Stauroneis phoenicenteron. 



Surirella biseriata. 



Surirella ovalis. 



Surirella robusta. 



Surirella spiralis. 



Synedra acus Kiitz. 



Synedra capitata. 



Synedra radians Kiitz. 



Synedra ulna Ehr. 



Tabellaria fenestrata Kiitz. 



Conjugatae 



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 121,653 331,687 420,463 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. 



