250 LORANDE LOSS WOODRUFF 
3. C Infusions 
Monad. Monads appeared only in inappreciable numbers in 
all the groups of infusions. In group IV, however, a number of 
monad forms, other than those included in the top counts, ap- 
peared in considerable numbers for a time. 
Colpoda. Practically no Colpoda were recorded for groups I 
and III. Group IV showed a brief maximum of 2500 per ce. which 
coincided with that of the top. 
Hypotrichida. The hypotrichous fauna was practically zero. 
Paramaecium. Paramaecia were not observed, except in group 
I where 100 per cc. were recorded for five days after a rapid 
decline at the top. 
Vorticella. Practically no Vorticella appeared in the bottom 
counts. 
Amoeba. In group I a few amoebae appeared on the 45th 
day and reached a maximum of 250 per ce. within the next five 
days, and then disappeared with equal rapidity. A heavy growth 
of 10000 tiny amoebae was attained in group III by the twenty- 
fifth day, and all were practically gone within ten days. In 
group IV a maximum of 10000 tiny amoeba was recorded on the 
20th day and from this time the number gradually decreased 
until the 47th day when very few were observed. This decline 
was followed by a rapid rise to about 2000 per cc. on the 56th 
day when the last count was taken. 
V1l. DISCUSSION AND CONCLUSIONS FROM THE OBSERVATIONS 
ON THE SEQUENCE OF THE SURFACE, MIDDLE 
AND BOTTOM FAUNA 
1. Surface fauna. 
These extended observations on the protozoa of typical labor- 
atory infusions, made up by several different methods, clearly 
indicate a definite succession of certain representative forms at the 
surface of the water.¥ 
13 T amindebted to Mr. T. 8. Painter, one of my students, who made for me a 
careful study of a number of similar infusions in the Yale Laboratory and also at 
his home in Salem, Virginia. His observations show an essentially comparahle 
