PROTOZOAN FAUNA OF HAY INFUSIONS Dove 
when it began a period of great abundance, reaching a maximum 
of 3500 per ce. from the 48rd to the 50th day. It then declined 
to about 1600 per ce. on the 57th day when the last count was 
taken. Vorticella attained a higher maximum than any other 
protozoon in this group of infusions. 
BI group. Vorticella appeared on the 18th day, rose to about 
200 per ce. on the 21st day and fell to 20 per ce. on the 26th day. 
It continued in about this abundance up to the 34th day when it 
multiplied rapidly and produced a maximum of about 1000 
per ce. by the 37th day. This was followed by a rapid decline for 
a few days and then a slow decline to the 67th day when the form 
became extinct. 
BII group. Vorticella appeared on the 5th day and fluctuated 
in numbers under 200 per cc. until the 45th day when the maxi- 
mum of 300 per ee. occurred. This was followed by a rapid de- 
cline resulting in extinction by the 50th day. 
B III group. This genus appeared on the 16th day and per- 
sisted in very small numbers, reaching its maximum of 120 per 
cc. on the 59th day. It had decreased somewhat by the 64th day 
when the last observation was made. 
BIV group. In this group Vorticella appeared on the 2nd day 
and persisted in numbers less than 200 per cc. until the 11th day, 
then arose abruptly to 3500 per ec. on the 16th day, and fell 
almost equally abruptly to about 20 per cc. by the 26th day. It 
persisted in approximately this number to the last count on the 
36th day. 
CI group. In this group of three infusions, the curve for Vor- 
ticella shows a peculiar series of fluctuations. The form appeared 
on the 44th day, rose to 500 per cc. by the 57th day, fell to 20 
per cc. by the 67th day, rose again to practically 500 per cc. by the 
74th day, fell again to about 20 per cc. by the 81st day and then 
had still another rise which brought the organism to its maximum 
on the 86th day, when the last observation was taken. 
C III group. Vorticella appeared and attained its maximum of 
100 per cc. on the 38th day in this infusion. From this time it 
very gradually decreased in numbers until the 65th day when the 
final count was made which showed about 50 per ce. 
