PROTOZOA AND THE UTRICLES OF UTRICULARIA. 267 



Experiment M. n. O'olpidia were inoculated into 24 attached bladders (6 on 

 each of 4 stems) that had previously been irrigated. They were active in at least 

 8 of these bladders 23 hours later. 



I:.v pt-r intent M. S. Colpidia lived at least 48 hours in liquid drawn from 15 

 Madders and kept in a moist chamber in a hollow ground slide. 



Experiment M. 10. Colpidia lived at least 44 hours in liquid drawn from 15 

 bladders that had recently killed paramecia. 



CMlomonas paramecium is captured by bladders. The medium 

 used in Experiments 10, 24, and 25 contained many specimens 

 of C. paramecium as well as paramecia, and it was noted that 

 many of both the attached and detached bladders captured 

 them. In some cases they may have entered at the same time 

 paramecia were taken in but they were also present in bladders 

 that had not captured paramecia. 



Material containing intestinal flagellates of tadpoles quickly kills 

 bladders. Four attempts were made (Experiments 3, 14, 21 and 

 22) to determine whether Trichomonas augusta, Hexamitus 

 batracliorum, and Euglenamorpha hegneri from the intestine of 

 tadpoles would be captured by and live in the bladders. Bladders 

 were immersed in diluted intestinal contents containing these 

 flagellates, and both attached and detached bladders were 

 inoculated with them, but the bladders were quickly killed 

 hence no definite results were obtained. 



Nematodes and rotifers are captured by and live in bladders for 

 many hours. 



Experiment 4. Several stems were immersed in a culture containing both 

 euglenas and free-living nematodes; two days later 7 of the 13 bladders contained 

 from i to 4 or more nematodes most of which were active. 



Active rotifers were found in many of the bladders recently 

 brought into the laboratory. These remained active for several 

 days indicating that they are able to withstand conditions within 

 the bladders for a considerable period. 



SUMMARY AND CONCLUSIONS. 



Summary, i. The bladders (utricles) of Utricularia vulgaris 

 v. americana Gray capture large numbers of small free-swimming 

 aquatic organisms; those on parts of a plant 220 cm. long 

 contained approximately 150,000 entomostraca and many other 

 organisms. 



