ii6 



AQUATIC MICROSCOPY FOR BEGINNERS. 



Fig. 92. — AmcEba pr6teus. 



of the soft and inconstant creature. When active it 

 never has precisely the same form twice in succession, 

 and seldom keeps its shape unchanged for two consec- 

 utive moments. The pos- 

 terior extremity, when the 

 Amoeba is in motion, ma,y 

 be entirely smooth, or it 

 may show a cluster of very 

 short pseudopodia, giving 

 it a velvety or mulberry- 

 like appearance. Suddenly 

 a blunt, 'thick finger pro- 

 jects from the part, and 

 Amoeba at once reverses its 

 course, the pseudopodia at 

 the front being withdrawn, 

 and disappearing in the sub- 

 stance of the body. The observer can never predict 

 what an Amoeba will do next. 



It is common in the ooze of shallow ponds and on 

 the leaves of many aquatic plants. Its body generally 

 contains a number of diatoms, which form part of its 

 favorite food, and it is a strange fact that the food is 

 usually taken by what, at the time, is the posterior ex- 

 tremity. There are several species. 



1. Body large, colorless or enclosing many blackish, 



movable, crystalline bodies; pseudopodia finger- 

 like, blunt. Amoeba prdteus, Fig. 92. 



2. Body small, colorless, rather sluggish; often float- 



ing freely, and star-shaped, with several conical, 

 acute, straight, or curved pseudopodia radiating 

 from the spherical body. The form changes very 

 slowly. A. radidsa. 



