Till'; I'KOTOZOA OF THK PITCH KR PLANT. 2/5 



from 15 of the 22 pitchers during this period. They may have 

 been present in all, since it was discovered later that the para- 

 mecia tend to congregate at the bottom of the pitcher where the 

 liquid is rich in organic debris; whereas the samples were taken 

 from the liquid near the top. There was an evident increase in 

 the number of paramecia present in at least 3 of the pitchers. 

 Colpoda was recovered from 1 1 pitchers and apparently had 

 multiplied in 4 of these. 



3. Paramecium in unopened pitchers in the laboratory: 

 Several cc. of culture medium containing paramecia were intro- 

 duced into each of 4 unopened pitchers and the lips of the pitchers 

 fastened together to prevent the entrance of insects. Samples 

 were examined from these daily for 12 days. In 2 of the pitchers 

 paramecium, and also colpoda and chilomonas, were more 

 abundant at the end of the experiment than at the beginning; 

 in the third pitcher paramecium was present in about the same 

 numbers as at first; colpoda and chilomonas had increased; 

 and in the fourth pitcher paramecia were present on the tenth 

 day but absent on the eleventh and twelfth days; colpoda 

 decreased in numbers but chilomonas had increased. 



4. Paramecium in open pitchers in the field: In order to 

 avoid the possibility that changes might occur in the pitcher 

 liquid when plants are brought into the laboratory, paramecia 

 were introduced into ten pitchers borne by 5 plants in the field. 

 These were labelled and examined on the following day and 2 

 days later. Paramecia were present in only 2 samples taken 

 after 24 hours, colpoda in 7 and chilomonas in 7. On the second 

 day the pitchers were brought into the laboratory, except one 

 which had lost its label and could not be identified, and para- 

 mecia were recovered in all 9 of them. Apparently no decrease 

 in numbers had occurred in the 48 hours of the experiment and 

 increases seemed probable in several pitchers. The reason 

 paramecia were found on the first examination in only 2 pitchers 

 is that the organisms had congregated near the bottom of the 

 pitcher where food conditions were favorable and, therefore, 

 could not be recovered from the samples which were taken near 

 the surface. Colpoda and chilomonas were recovered also from 

 all 9 pitchers with no apparent decrease in numbers. 



