ON THE FEEDING HABITS OF AMEBA 561 



four minutes. Then the anieba gradually withdrew from the 

 carmine, the food cup remaining uncompleted. The ameba 

 moved only slightly for about ten minutes thereafter, then two 

 flagellates were caught in a large food cup. Two minutes later 

 a pseudopod was thrown out on either side of the carmine for a 

 short distance, but these were withdrawn as a spathidium (?) 

 was encountered and ingested in a large food cup. The spathid- 

 ium moved about in the food vacuole for about eleven minutes. 

 This unusually long time of activity of the captured prey may 

 have been due to a partial exhaustion of the ameba's digestive 

 juices, as a result of its reactions to carmine in the experiment 

 where the carmiaie grain was only three-fourths surrounded, 

 but held in the food cup for about six minutes — 108 — 111. 



Two days later a new grain of carmine of grade 2 was then laid 

 on the surface film near the ameba, which was at this time crawl- 

 ing along the surface film — 122. The carmine grain was rolled 

 around for eight minutes. The ameba then moved away. 

 About three hours later a fresh piece of carmine of grade 2 was 

 laid into contact with the ameba, now on the bottom of the dish — 

 129. A food cup was at once formed in which half of the carmine 

 was enclosed. After the ameba had remained quiet for several 

 minutes, the food cup was retracted and the carmine carried to 

 the back of the ameba. A few minutes later the carmine rolled 

 off and the ameba moved away. 



Next day a small piece of a worm, aelosoma, was laid in the 

 ameba's path, but no definite change of behavior resulted. A 

 fresh piece of carmine of grade 2 produced a positive reaction, a 

 pseudopod being sent out toward it — 139. There was no indica- 

 tion of a food cup, and soon the ameba moved away. The same 

 carmine grain was then shifted so that it lay in the ameba's 

 path — 143. Again there was a slight positive reaction, after which 

 the ameba moved off. 



Two days later a piece of Knox Sparkling Gelatine, which was 

 placed in the ameba's path — 148 — produced a shght positive 

 reaction, after which the ameba moved on. 



The behavior of this ameba toward carmine may be summa- 

 rized as follows : Fresh grains of carmine containing only a slight 



