PART I 



THE BEHAVIOR OF UNICELLULAR ORGANISMS 



CHAPTER I 



THE BEHAVIOR OF AMCEBA 



i. Structure and Movements of Amoeba 



The typical Amoeba (Fig. i) is a shapeless bit of jelly like protoplasm, 

 continually changing as it moves about at the bottom of a pool amid 

 the debris of decayed vegetation. From the main protoplasmic mass 

 there are sent out, usually in the direction of locomotion, a number of 



Fig. i. — Amceba proteus, after Leidy (1879) (slightly modified), c.v., contractile vacuole; 

 ec, ectosarc; en., endosarc; nu., nucleus; ps., pseudopodia. 



lobelike or pointed projections, the pseudopodia (Fig. 1, ps.). These 

 are withdrawn at intervals and replaced by others. Within the mass 

 of protoplasm certain differentiations are observable. Covering the 

 outer surface there is usually, though not always, a transparent layer 



