84 University of California Publications in Zoology [Vol.22 



Tintinnidium fluviatile St. 



Station I Station TI Station III Daily Hourly 



Average 17,333 3,359 8,642 7,341 323,479 



Identification uncertain. Loss through net probably heavy. For 

 some reason (probably because intent on Difflugia) the writer entirely 

 overlooked this form and that of CodoneUa until attention was forci- 

 bly attracted by some living material in 1914. This was after the 

 count had progressed almost through the first seven months of 1913, 

 hence it was too late to rectify by recounting. It was also impossible 

 at that late date to distinguish the three forms readily in preserved 

 material. Undoubtedly some CodoneUa and a few Difflugia are in- 

 cluded under the present head. It is also probable that Difflugia in- 

 cludes some of both Tintinnidium and CodoneUa even after an attempt 

 was made to differentiate them. CodoneUa was not successfully dis- 

 tinguished at all. The count as it stands yields very imperfect results. 

 It appears certain, however, that Tintinnidium does best in heavy 

 sewage. Since the river shows least of this species it is also probable 

 that quiet water is favorable. So far as the evidence goes, it seems 

 that higher temperatures are best. 



Trichoelina pediculus Ehrbg. 



Average at Station I, 631. 



Identification probable. Loss through net probably heavy. Occur- 

 rence at Station I almost entirely in first three and last three months. 

 Recorded only once at Stations II and III. Small numbers every- 

 where. Surely a cold water form favored by sewage. Adventitious. 



Vorticella longifilum Ehrbg. 



Station I Station II Station III Daily Hourly 

 Average 13,991 2,588 3,612 413 



Identification doubtful. Count includes all individuals with very 



long and slender stalks. None were ever found attached to anything. 



Loss through net probably very heavy. Occurrence at Station I 



mainly in last three months. Catches in small numbers and at widely 



separated and irregular intervals at other times and other stations. 



Evidently a cold water form doing best in sewage and quiet waters. 



Vorticella sp. 



Station I Station II Station III Daily Hourly 



Average 623,067 274,328 300,528 1,153,087 1,797,514 



Identification uncertain. Probably includes several species of 



short stemmed Vorticella and some craspeinonad flagellates attached 



to various objects. 



