92 University of California Publications in Zoology [Vol.22 



Anuria opsis si>. 



^ ^ Station I Station II Station III Daily Hourly 



Average 8,230 308 4,619 26,867 



Identification doubtful. Record probably includes two or three 

 small forms with indistinct characteristics in the preserved condition. 

 Referred to this genus as the nearest probability. May include dis- 

 torted specimens of A. fissa. Since the only records of this form are 

 in June and July at the three stations, it may be that the whole num- 

 ber should be transferred to A. fissa. 



Asplanchna brightwelli Gosse. 



Station I Station II Station III Daily Hourly 



Average Ki.MiL' 308 533 43,192 2,954 



Species determination uncertain. Genus certain. Record prob- 

 ably includes at least two or three species under this heading, species 

 segregation being too difficult during the count. Eggs not counted. 



Occurrence at Station I regular from mid-March to November I. 

 Maximum, 158,688, on July 5 but almost equalled in April and Octo- 

 ber. Recorded only three times at Station II in April, June and 

 July in small numbers. Recorded five times at Station III from 

 March to November in small numbers and at wide intervals. Dis- 

 tinctly favored by sewage and by temperatures near 20° C. 



The record at Station I shows ten fairly distinct pulses, seven of 

 which followed pulses of chlorophyll bearing organisms by from three 

 to seven days, two of which coincided with such pulses, while one 

 preceded. The correlation of these pulses is far the most impressive 

 of any yet observed. The following table, text table 3, shows tem- 

 peratures and pulses: 



April 9 IS 



May 11 21 



June 7 25 



Aug. 2 26 



Sept 13 25 



Asplanchnopus sp. 



Identification doubtful. Recorded three times each at Stations I 

 and II and six times in hourly series at Station III. Not important. 



Brachionus. 



Identification of the females of this genus was nearly always satis- 

 factory as to genus but the separation of species was frequently dif- 

 ficult and sometimes impossible. Males were never positively recog- 

 nized, hence species records were of females only. Eggs were easily 



