60 Urwversity of California Publications in Zoology [Vol.22 



failure to decide to record it. There is enough record to indicate 

 that it is a warm weather form and not nearly so well represented in 

 the colder months. 



Synedra ulna Ehrbg. 



Station I Station II Station III Daily Hourly 



Average 655,730 730,339 744,781 2,351,197 305,169 



Identification uncertain. Probably includes at least three or four 

 other species with possibly some similar genera. This probably ac- 

 counts for the similarity of numbers and distribution at all stations. 

 Maximum in August at Stations II and III, in June at Station I 

 with a large pulse in August. Certainly favored by higher tempera- 

 tures. Losses through net heavy. An important local planktont. 



Tabellaria spp. 



Identification of genus satisfactory. Occurrence at all stations 

 rare. Evidently unimportant here. It was thought that both T. 

 fenestrata and T. flocculosa were recognized a few times. This genus 

 is apparently no more at home here than Kofoid (190S) reported it 

 to be in Illinois. 



The following forms of Bacillariaceae were recorded only once 

 or twice at the three stations, or were thought to be recognized in 

 living material: 



Amphora coffeaeformis Ag. Once, I and twice, III. 



Amphora sp. Once, I and III. 



Cocconeis placentula Ehrbg. Once, II. 



Cocconeis sp. 



Coscinodiscus sp. Once Stations I and III and daily. 



Cyclotella schroeteri Lemm. Once, I. 



Cymbella helvetica Kiitz. Once, II and III. 



Cymbella lanceolata Ehrbg. 



Cymbella parva W. Sm. Twice, I, once at II and III. 



Cymbella pusilla Grun. 



Cymbella prostrata Berk. 



Denticula sp. 



Diatoma sp. 



Diatoma vulgare Bory. Twice, I, once at III. 



Diatomella sp. Grew Once, I and II. 



Epithemia granulata Ehrbg. 



Epithemia sorex Kiitz. Once, III. 



Epithemia sp. 



Epithemia turgida Ehrbg. Once, II. 



Eunotia flexuosa Kiitz. Once at Station I, twice at III. 



Eunotia major W. Sm. Once, III. 



Eunotia pectinalis Kiitz. 



Fragillaria mutabilis. 



