RHIZOPODS. 115 



the first seen, as a colorless, jelly-like body, very soft, 

 and changeable in shape, slowly moving forward and 

 suddenly altering its course and extending itself in nu- 

 merous long, blunt, finger-like pseudopodia, lengthening 

 or shortening at the creature's will. Or he may see 

 a small pear-shaped collection of sand-grains slowly mov- 

 ing about the slide, apparently without a cause, but a 

 careful examination of the narrow or stem end of the 

 pear will show the long, fine, and colorless pseudopodia 

 issuing from the mouth, and he will know it to be a 

 Rhizopod. After he has recognized a living shell he 

 will have no trouble thereafter in knowing a dead one, 

 and by referring to the following Key he will be able 

 to learn its name, unless it is a very uncommon species. 



Key to Genera of Rhizopods. 



1. Body without a shell (a). 



2. Body with a shell (e). 



a. "Without fine, hair -like rays; pseudopodia thick 



and blunt (b}. 

 a. With fine, hair-like rays on all parts of the body 



w- 



I). Body colorless, very changeable in shape. Amoe- 

 ba, 1. 



c. Body orange or brick -red, with pin -like rays. 

 Vampyrella, 2. 



c. Body colorless or greenish (d). 



d. Eays stiff, forked at the ends ; body often green. 



Acanthocystis, 3. 

 6* 



