FOOD-REACTIONS OF PELOMYXA 391 



position (2, fig. 11). Protoplasm overarched the somewhat 

 triangular bay and eventually the specimen was crowded into 

 a relatively small food vacuole and quieted. 



Reactions once started may or may not be reversed when 

 the prey escapes. 



October 23, 1916. This observation was based upon one 

 of the four parts into which an individual had been divided on 

 October 19. In this case a small, very active ciliate (about 

 the size of Chilomonas) entered the angle between the two 

 anterior pseudopods A and B, figure 12. This ciliate glided 

 back and forth along the middle third of the mesial surface of 

 pseudopod A. This pseudopod widened to contour a-a and 

 a' -a' and then small pseudopods b and b' arose one to each side 

 of the persistently gyrating ciliate, while a similar pseudopod 

 c arose from the mesial surface of B. The ciliate, however, 

 escaped at this point along the path indicated by arrow y. 

 Pseudopods b, b', and c were then retracted and pseudopod A 

 narrowed. 



November 13, 1916. A specimen of Pelomyxa, that had in 

 its posterior end an ingested paramaecium which was pulled 

 into a bilobed contour, approached along its main axis a group 

 of three paramaecia. The anterior end became bifurcated 

 before a contact had been made with the ciliates. This bifurca- 

 tion continued resulting in the formation of pseudopods a and 

 a', fig. 13 A. The remotest of the three paramaecia retreated 

 before the reaction had well set in. Pseudopods a and a' ad- 

 vanced until the latter collided with the nearest paramaecium 

 and drove it away. The third paramaecium was disturbed 

 and chased away by pseudopod b r hitting it. There were now 

 no objects of prey within the enclosed bay and yet b bent upon 

 itself in its advance to c, while c' crossed in beneath c as a pro- 

 longation of b' . Furthermore a thin overarching pseudopod 

 d arose from the fundus of the bay and as it expanded, to meet 

 the expanding, overarching margins of a, a', b, b' and c' the 

 completion of a well formed food vacuole was effected. 



This same specimen a little later had a Paramaecium strike 

 its anterior end to which it responded by sending pseudopods 



