68 University of California Puhlications in Zoology [Vol. 22 



two stations are not mueli better. Evidently we have again too much 

 influence of (Jhramulina in the record. Since the only other flagel- 

 late showing very large numbers is Trachclamonas, itself very small, 

 it seems hardly worth while to attempt any conclusions from net col- 

 lections. 



Discussion of Species 



Ceratium liirundindla 0. F. Miill. 



Identification satisfactory. Loss through net probably very heavy. 

 Occurrence rare and in small numbers, four times at Station I in 

 September and October. Five times at Station II in June, July, Au- 

 gust and September. Three times at Station III in July, September 

 and October. 



Cercomoiia,<i crassicduda Duj. 



Identification satisfactory. Loss through net very heavy. Occur- 

 rence rare and in small numbers. Recorded at Station I nine times 

 at wide intervals from July to the end of the year. Twice at Station 

 II in July and September. Five times at Station III in June, August 

 and September. 



Cercomoncws sp. 



Identification of genus doubtful. Recorded seven times at Station 

 I in August and September, and once at Station III. 



Chlamydomonas sp. 



Identification of genus doubtful. Recorded eight times at Station 

 I from July to December, five times at Station II from May to October 

 and twice at Station III in February and May. 



Chromulina spp. 



station I Stiition II Station III Daily Hourly 



Average 2,760,969 2,225,384 2,241,982 4,136,123 30,256,512 



Identification uncertain. Ma.v include various minute genera not 

 readily distinguished while counting. Percentage retained by net 

 surely very small. Found in every month at all stations but occa- 

 sionally not recorded in the first half year. Constantly present after 

 July. Maximum at Station I on September 13, Station II on Octo- 

 ber 26, and Station 111 on November 22. Evidently favored by warm 

 and quiet water and not much atl'ected by sewage. 



