274 K. \V. IlKGNER. 



protozoa found living in the pitchers may be of two types, 

 (i) free-living species and (2) species adapted for life in the 

 pitcher liquid and restricted to this habitat. The pitchers are 

 visited by many insects which are drowned in the liquid and 

 these no doubt are frequently soiled with material containing 

 cysts or even living trophozoites of free-living protozoa. This 

 seems to be a simple avenue for the entrance of free-living 

 species. Species that may be peculiar to the pitchers may 

 similarly be transferred from one pitcher to another by the 

 insects that live in the pitcher plant liquid and which fly from 

 pitcher to pitcher to lay their eggs. 



Experimental Studies on Free-living Protozoa in Pitcher Liquid. 

 Paramecia were the principal protozoa used in these experi- 

 ments; Colpoda and Chilomonas were present in some of the 

 paramecium cultures. Four types of experiments were per- 

 formed; (r) paramecia were introduced into pitcher liquid in 

 hollow ground slides, (2) into open pitchers in the laboratory, 

 (3) into unopened pitchers in the laboratory and (4) into open 

 pitchers in the field. 



1. Paramecia in pitcher liquid in hollow ground slides: In 

 three experiments liquid from 24 pitchers on plants brought into 

 the laboratory was used. Five drops of liquid from each pitcher 

 were placed in one hollow ground cavity of a slide and one drop 

 of culture medium containing paramecia was added; live drops 

 of culture medium were placed in the other cavity and one drop 

 containing paramecia added. All the preparations were ex- 

 amined at frequent intervals during the first two days but after 

 that daily for from 5 to 7 days. In every preparation the 

 paramecia lived as well in the pitcher liquid as in the culture 

 medium, and although no exact count was made, it was evident 

 that multiplication occurred in at least 8 of the samples of 

 pitcher liquid. 



2. Paramecia in open pitchers in the laboratory: Paramecia 

 were introduced into the liquid in 22 pitchers on four plants in 

 the laboratory. The liquid in these pitchers was present when 

 the plants were brought in. Eight of the pitchers were old, 

 8 mature, and 6 young. Samples were taken from these pitchers 

 daily during the succeeding 5 days. Paramecia were recovered 



