78 Jhiivcrsitij of Califdrnui Piihliciiiions in Zoolutjij [\'oi,. 22 



Heliozoa 



Station I Station II Station III Daily Hourly 



Number of forms rccordcil 8 6 10 4 4 



Individuals per cu. meter.. 370,995 257,232 274,580 619,156 441,478 



While there were only a few species of Heliozoa recorded the 

 numbers of some of tlie smaller forms were quite large and so make 

 the group somewhat important. The extreme fragility under manipu- 

 lation makes detailed examination somewhat untru.stworthy in results 

 and also invalidates the count more than in the other groups. Never- 

 theless the following records seem to be fairly satisfactory. Through 

 some error in copying early lists, Nuclcaria and Vampyrella were in- 

 cluded with Rhizopoda. The numbers do not seriously change the 

 totals in the two groups, however; the totals for Heliozoa have been 

 left short by that much and the totals for Rhizopods show a corre- 

 sponding excess. 



Discussion of Species 

 Heterophrys fockei Arch. 



station T Station II Station III Daily Hourly 



Average 24,459 139,328 98,532 55,170 207,538 



Identification uncertain. May include other species or other 

 genera at times. Thought to be usually correct. Not recorded at any 

 station before July. Not present at any after October. One of the 

 most definitely limited organisms on our records. Limited to a period 

 of about sixteen weeks with a peculiar break in the middle (last of 

 August). This is a period in which the temperature was almost con- 

 stantly above 20° C. Maximum numbers on August 2 at Station I, 

 October 4, at Stations II and III. Smaller numbers at Station I in- 

 dicate deterrent action of sewage. 



JJetcroplirys sp. 



Probably not deserving separate listing though this fact was not 

 discovered until too late to change easily. ' 



Nuclearia simplex Cienk. 



station I Station II Station III Daily Hourly 



Average 7,020 338 15,871 206 44,758 



Identification uncertain. No records until late in the season, 

 partly because overlooked until October, partly because of indecision 

 as to advisability of recording. It was finally decided that some indi- 

 cation of the presence of an organism possibly belonging under this 

 species name was desirable. No conclusions can safely be drawn as 

 to distribution, however. 



