94 



Merl, E. M. 'Biologischen Studien ueber die Utriculariablase.' Flora, 15: 



(N.F.) : 59-74- 1922. 

 Skutch, a. F. 'The capture of prey by the Bladderwort. A review of the 



physiology of the bladders.' New Phyt., 27: 261-297. 1928. 

 WiTHYcoMBE, C. L. a. 'Observations on the Bladderwort.' Knowledge, 13, 



part 12 (N.S.) : 238-41. 1916. (Not directly consulted.) 



b. 'On the function of the bladders in Utricularia vulgaris Linn. ; 



Journ. Linn. Soc. Bot., 46: 401-13. 1924. 



DESCRIPTIOX OF FIGURES 



1. Utricularia gibha L. Portion of plant, about twice natural size. 



2. Section of doorstep. 



3. Diagram of section of doorstep, a, bifid hairs on inner slope of 

 the step, b, the pad of modified hairs forming the doormat, c, the veil, d, 

 slender hairs which are numerous in the vestibule, e, glandular hair of the 

 outer wall. 



4. A single bladder photographed : A. in the set condition, B. after 

 tripping, C. after pricking the wail. 



5. One-half of a doorstep viewed from above. To the left is shown 

 the sloping portion merging with the lateral wall of the bladder, below is 

 the inner edge of the step with its bifid hairs, above is the veil. 



6. A bladder tripped in air, showing the air bubble swallowed by it. 



7. Successive frames from motion picture. In the upper photograph 

 the worm is outside the trap, in the lower it has been engulfed. Time 

 interval about one-sixteenth of a second. 



8. A detached trap that has swallowed a glass rod which tripped it. 



9. In this case the door closed on a worm and jammed it against 

 the doorstep. 



10. A living trap viewed from the front to show the veil. 



11. Anterior portion of bladder with- part of the lateral wall cut 

 away to show the door, the four trigger-hairs and the doorstep. Note the 

 remains of a worm and a copepod. 



12. Inner wall of bladder with quadrifid hairs. 



