3o TOILERS IN THE SEA. 



that the Amoeba is a minute jelly-like animal, 

 which has no special form of its own, but is sub- 

 ject to incessant changes of form, by thrusting out 

 portions of its gelatinous substance, and retracting 

 others, moving slowly from place to place by means 

 of these foot-like extensions of the body, called 

 pseudopodia, or false feet. "On coming in contact 

 with any particle of organic substance, on which 

 the Amoeba is inclined to feed, and they obvi- 

 ously have some choice in this respect, the sarcode 

 proceeds to surround it, so that it is soon enclosed, 

 along with some water, within the body. Most 

 observers agree in believing that any part of the 

 body may thus incept the food, though some have 

 believed in an oral aperture (mouth). No such 

 aperture has been discovered, and the evidence 

 does not indicate its existence. It also appears in- 

 disputable that when the Amoeba has extracted the 

 nourishment from the food, it ejects what remains, 

 but not at the spot where the food entered. This 

 is done at the posterior extremity of the body, 

 where also the contractile vesicles discharge them- 

 selves. Writers speak of an anal outlet at this 

 point, but there is no reason for believing in its 

 presence. The particles appear to be simply forced 

 out through the sarcode." l 



1 "The Amoeba," by Prof. W. C. Williamson, in Popular 

 Science Review ', vol. v. (1866), p. 188. 



