388 WM. A. KEPNER AND J. GRAHAM EDWARDS 



< posterior' end of the body-proper, the little plant had been 

 quieted and lay within a vacuole whose diameter was about 

 twice the length of the Cryptomonas. 



October 23, 1916. This reaction also was observed on one 

 of the individuals arising when a Pelomyxa had been cut into 

 four parts on October 19. We found a Paramaecium caudatum 

 (fig. 7-1), 'tickling' the 'anterior' end repeatedly bj^ darting 

 against the Pelomyxa and then retreating and again advancing 

 to encounter the Pelomyxa at another part of its greatly ex- 

 panded end. While we waited for a response to these recur- 

 ring contacts a Loxocephalus came to play repeatedly against 

 the anterior end at the position 3 in figure 7. In response to 

 these two sets of stimuli, pseudopods a and a' arose. The 

 second one of us was now called in to collaborate in this obser- 

 vation. Pseudopods a and a' advanced to contours b and b' . 

 About this time a second Paramaecium caudatum entered the 

 breach and lay in the partily enclosed space. Next b and b' 

 met at c and c'; but there was nd fusion of the ectoplasm of 

 c and c' '. The inner margins of c and c! widened to form up- 

 ward-projecting films of protoplasm d and d' ; film d elongated 

 and passed down by the side of d' to widen the over-arching 

 protoplasm along contour e. The ciliates now began to show 

 signs of uneasiness and darted to and fro hitting the edges of 

 the enclosing pseudopods which could be clearly seen to deflect 

 the ciliates towards the surface film of the hanging drop 

 of water. 



Next there appeared two outer pseudopods / and /', which 

 at no time became active. Finally g, h, i, as broad bands of 

 over arching cytoplasm, came up over the space enclosing the 

 three ciliates and eventually fused with the inner margins of 

 d and e to complete the enclosing vault of the trap — the surface 

 film of the hanging drop forming its floor. Next the space was 

 divided, k and other parts of protoplasm forming a constriction. 

 In one secondary space a paramaecium was enveloped and in 

 the other the second paramaecium and the Loxocephalus were 

 enclosed. These secondary spaces were finally reduced greatly 

 and in the end each paramaecium was divided into three parts — 



