244 LORANDE LOSS WOODRUFF 
A similar analysis of the data of the A, B, and C series of infu- 
sions separately shows the following sequence: 
A Series 
APPEARANCE MAXIMUM 
(1) Monad (1) Monad 
(2) Colpoda (2) Colpoda 
(8) Hypotrichida (8) Hypotrichida 
(4) Paramaecium (4) Paramaecium 
(5) Vorticella Vorticella 
(6) Amoeba i‘ (5) cine 
B Series 
APPEARANCE MAXIMUM 
(1) Monad (1) Monad 
Colpoda Colpoda 
2) ee ee (2) awe a. 
(3) Paramaecium (3) Paramaecium 
(4) Vorticella (4) Amoeba 
(5) Amoeba (5) Vorticella 
C Series 
APPEARANCE MAXIMUM 
(1) Monad (1) Monad 
(2) Colpoda (2) Colpoda 
(8) Hypotrichida (8) Hypotrichida 
(4) Paramaecium (4) Paramaecium 
(5) Vorticella (5) Vorticella 
(6) Amoeba (6) Amoeba 
V. PROTOZOAN FAUNA AT THE MIDDLE OF THE INFUSIONS 
It is evident, from the observations on these infusions, that the 
protozoan fauna of the middle of the infusions is meager, com- 
pared with that of the top and bottom. Practically all the organ- 
isms which have been observed at either the top or bottom have 
been found in the middle counts; but either in such small numbers, 
or so irregularly, as to make a detailed tabulation of the records 
of little value. Therefore they are not presented here. Bio- 
logically, the middle of the infusion clearly offers a less favorable 
environment than either the top or the bottom, and is therefore 
tenanted chiefly by a free-swimming population brought there by 
an overcrowding at the top or bottom, and by forms emigrat- 
ing from the top to the bottom as the cycle proceeds. Naturally 
