PARAMECIUM 3 



C. Movements. 



The constant but slow change of form already referred 

 to is known as ' amosboid movement.' Pseudopodia are 

 protruded from any point of the surface, and can be com- 

 pletely withdrawn, and a slow crawling movement of the 

 whole animal can be effected by their means. Pseudopodia 

 may also surround particles of food and then be withdrawn, 

 bringing the food-particles into the body. 



Draw a specimen of Amoeba several times at intervals of 

 half a minute, indicating the direction of flow of the particles 

 by means of arrows. Compare the drawings, and note the 

 differences of form even in sluggish specimens in luhich move- 

 ment was not obvious. 



Feed ivith indigo or carmine, or other finely divided 

 pigment, and note that food is taken in at all parts of the 

 surface. 



D. Reproduction. 



Amoeba multiplies by fission ; that is, the whole mass 

 divides into two, each containing a portion of the nucleus, of 

 the endosarc, and of the ectosarc of the original cell. 



II. PARAMECIUM AURELIA. 



This is a free -swimming freshwater protozoon found 

 abundantly amongst decaying vegetable matter. It differs 

 from Amoaba in its more definite shape ; in the more marked 

 differentiation of ectosarc and endosarc ; in the presence of 

 cilia and the absence of pseudopodia ; in its active locomotion 

 by means of the cilia; and in the possession of a definite 

 mouth, and of definite dorsal and ventral surfaces, and ante- 

 rior and posterior ends. 



Put a drop of water containing Paramecia on a slide ; 

 spread a very little cotton wool over it, to limit the move- 

 ments of the animals ; cover, and examine with low and high 

 powers. 



B2 



