SECT. I 



PHYLUM PROTOZOA 



particles are to be recognised as endowed with life. But 

 Amoeba is not one of these. It is to be recognised as a 

 glassy-looking, irregularly shaped particle with a definite 

 outline. From a particle of some crystalline mineral sub- 

 stance, to which such a description would equally well apply, 

 Amoeba would soon be distinguishable owing to the 

 circumstance that it is constantly changing its shape. 



This change is effected by the pushing out of projections 

 or processes, called psetidopods or psendopodia (psd.), which 



FIG. i. Amoeba proteus, a living specimen, c. vac. contractile vacuole ; 

 . nucleus ; psd, pseudopods. (From Parker's Biology, after Gruber.) 



undergo various alterations of size and shape, and may become 

 withdrawn, other similar processes being developed in their 

 place. At the same time careful watching shows that the 

 Amoeba is also, with extreme slowness, changing its position. 

 This it effects by a kind of streaming motion. A pro- 

 jection forms itself on one side, and the entire substance of 

 the Amoeba gradually streams into it ; a fresh projection 

 appears towards the same side, the streaming movement is 

 repeated, and, by a constant succession of such movements, 

 an extremely gradual locomotion, which it often takes very 

 close watching to detect, is brought about. In these move- 



