66 University of California Publications in Zoology [Vol. 22 



PROTOZOA 



Static. n I Station II Station III Daily Hourly 

 Number of forms recorded 75 53 59 26 34 

 Average number of indi- 

 viduals per eu. meter 5,194,416 3,494,065 3,634,131 3,880,462 7,908,872 



The number of forms recorded is 116 but that is certainly consid- 

 erably less than the real number of species. Identification was very 

 difficult, not only of species but of genera. Many species were indis- 

 tinguishable under conditions of counting and some that were re- 

 corded for a time were abandoned later when high power study 

 showed how great the error was. Distortion of preserved material 

 was a great factor affecting accuracy of counting of Protozoa. Even 

 such strikingly different species as the two stentors, {S. coeruleus and 

 8. niger) could not be separated with full confidence during the 

 count. For these reasons the list of Protozoa shows more often than 

 that of algae names which include several forms within rather ill 

 defined limits. 



Notwithstanding the great diversity of characteristics shown by 

 several prominent protozoan planktonts, the distribution of totals 

 through the year at different stations deserves some attention. The 

 totals of non-flagellated Protozoa at all stations agree in that there is 

 light representation in January, February and December, with an 

 equally well defined heavy representation from May or July to mid- 

 November. Station I averages about 60 per cent higher on its totals 

 than either of the others but its maximum is only slightly greater. 

 The maximum for Station I falls on August 13 but it is almost 

 equalled by a similar pulse in November. The maximum for Station 

 II comes on October 4 and for Station III on August 15, but the latter 

 record is almost equalled by a further pulse on October 4. There is 

 then substantial agreement of all stations in making the best showing 

 as to large numbers and continuity of numbers in late summer and 

 through autumn, when temperatures are rather high, the water quiet 

 and the organic content great. 



The inclusion of the Mastigophora with the Protozoa almost de- 

 stroys the definiteness referred to above. Such a combination shows 

 at Station I a fairly well marked pulse in January, another in March 

 and another in April, followed by a steady increase up to the maxi- 

 mum on September 9. There were then two moderate pulses on the 

 decline, which was otherwise fairly steady to the end of the year. At 



