238 LORANDE LOSS WOODRUFF 
CIV group. Again in this series Vorticella passed through a 
series of fluctuations, beginning on the 19th day, reaching a 
maximum on the 32nd day of approximately 500 per cc., falling 
to nearly zero on the 37th day, and thereafter increasing in num- 
ber until there were about 240 per cc. present at the finalcount on 
the 56th day. 
A study of the data presented above shows that Vorticella 
usually attains its greatest abundance later than Paramaecium. 
6. Amoeba 
A I group. Amoeba was first seen on the 47th day, rose to a 
maximum of about 1000 per ce. by the 56th day and decreased 
until none were present on the 67th day. 
All group. This form appeared on the 21st day and fluctuated 
in numbers until the 50th day when it completely disappeared. 
It reappeared again on the 66th day and reached a maximum of 
about 1000 per cc. on the 75th day when the last count was made. 
A III group. Amoebae appeared on the 17th day and after 
various fluctuations attained a maximum of 2700 per cc. on 
the 57th day. After this they declined rapidly and had disap- 
peared by the 64th day when the last count was taken. 
A IV group. These forms were first seen on the 5th day and 
continued to be present, though in practically negligible numbers, 
until the 21st day. Then they began to multiply rapidly and 
attained a maximum of 2500 per ec. on the 32nd day. A sudden 
decline brought the number down to about 40 per cc. on the 36th 
day and zero was reached by the 50th day. 
BI group. Amoebae did not appear at all in one of the cultures 
of this group, and in the other a total of 22 amoebae were observed 
at different times from the 40th to the 87th day. 
BII group. Starting on the 23rd day, this form reached a per- 
iod of greatest abundance on the 45th day when about 100 per 
ee. were counted. Extinction occurred by the 55th day. 
BIII group. This form appeared on the 14th day and reached 
a maximum of 1000 per cc. on the 25th day. They completely 
disappeared by the 37th day. 
