THE BEHAVIOR OF AMCEBA 17 



I had attempted to cut an Amoeba in two with the tip of a fine glass 

 rod. The posterior third of the animal, in the form of a wrinkled ball, 

 remained attached to the rest of the body by only a slender cord, — 

 the remains of the ectosarc. The Amoeba began to creep away, drag- 

 ging with it this ball. This Amoeba may be called a, while the ball 

 will be designated b (see Fig. 21). A larger Amoeba (c) approached, 

 moving at right angles to the path of the first specimen. Its path acci- 

 dentally brought it in contact with the ball b, which was dragging past 

 its front. Amoeba c thereupon turned, followed Amoeba a, and began 

 to engulf the ball b. A cavity was formed in the anterior part of Amoeba 

 c, reaching back nearly or quite to its middle, and much more than 

 sufficient to contain the ball b. Amoeba a now turned into a new path ; 

 Amoeba c followed (Fig. 21, at 4). After the pursuit had lasted for 

 some time the ball b had become completely enveloped by Amoeba c. 

 The cord connecting the ball with Amoeba a broke, and the latter went 

 on its way, disappearing from our account. Now the anterior opening 

 of the cavity in Amoeba c became partly closed, leaving only a slender 

 canal (5). The ball b was thus completely enclosed, together with a quan- 

 tity of water. There was no adhesion between the protoplasm of b and 

 c; on the contrary, as the sequel will show clearly, both remained inde- 

 pendent, c merely enclosing b. 



Now the large Amoeba c stopped, then began to move in another 

 direction (Fig. 21, at 5-6), carrying with it its meal. But the meal — 

 the ball b — now began to show signs of life, sent out pseudopodia, and be- 

 came very active ; we shall therefore speak of it henceforth as Amoeba b. 

 It began to creep out through the still open canal, sending forth its 

 pseudopodia to the outside (7). Thereupon Amoeba c sent forth its 

 pseudopodia in the same direction, and after creeping in that direction 

 several times its own length, again enclosed b (7, 8). The latter again 

 partly escaped (9), and was again engulfed completely (10). Amoeba c 

 now started again in the opposite direction (11), whereupon Amoeba b, 

 by a few rapid movements, escaped from the posterior end of Amoeba 

 c, and was free, — being completely separated from c (11, 12). There- 

 upon c reversed its course (12), overtook b, engulfed it completely again 

 (13), and started away. Amoeba b now contracted into a ball and re- 

 mained quiet for a time. Apparently the drama was over. Amoeba c 

 went on its way for about five minutes without any sign of life in b. In 

 the movements of c the ball became gradually transferred to its poste- 

 rior end, until there was only a thin layer of protoplasm between b and 

 the outer water. Now b began to move again, sent pseudopodia through 

 the thin wall to the outside, and then passed bodily out into the water 

 (14). This time Amoeba c did not return and recapture b. The two 



