98 Viviversity of California Publications in Zoology [Vol.22 



occupied at least half of the space inside the lorica of the host. None 

 were noticed at Stations II and III so it is probable that sewage is 

 favorable to the parasites in some way. They were recorded five 

 times at Station I, one in June, thrice in August and once in Novem- 

 ber. 



Diurella egg, free. 



Station I Station II Station III Daily Hourly 



Average 4,161 146,079 108,270 4,445 122,068 



Identification very doubtful. Small eggs attached to filaments of 

 Melosira granulata were counted under this heading. They were only 

 recorded eight times at Station I but they were quite prominent at 

 the other stations, at Station II from June to October inclusive, at 

 Station III from May to October inclusive. Inasmuch as no consid- 

 erable number of Diurella females were ever found, it is probable 

 that these eggs were wrongly designated, but nothing is known as 

 to the real identity. 



Epiphanes clavulata Ehrbg. (Notommata.) 



Station I Station II Station III Daily Hourly 



Average 1,263 6,400 10,423 



Identification uncertain. Recorded five times at Station I, nine 

 times at Station II and seven times at Station III in August, Septem- 

 ber and October. Hence it is to be regarded as definitely limited to 

 stagnating waters and temperatures above 20° C. Sewage unfavor- 

 able. Attached female eggs were also recorded for this form at 

 Stations II and III. 



Filinia brachiata Rous. (Triarthra.) 



Station I Station II Station III Daily Hourly 



Average 2,943 123 62 206 



Identification certain. Recorded eleven times at Station I and 

 once at each of the other stations. Occurrence at Station I usually 

 in small numbers at rather wide intervals. Catches grouped in May 

 and November. Maximum in November. This species was not re- 

 ported as present in Illinois. 



Filinia eggs, attached. 



Station I Station II Station III Daily Hourly 



Female, average 79,131 554 1,004 12,667 



Male, average 24,818 431 251 



Identification certain. Attached female egg appeared in every 

 catch at Station I from February 12 to April 26, then frequently to 



