STRUCTURE OF AMCEBA 



47 



and many arte helpful to us in that they serve as food for 

 fishes. Others, however, may become parasitic in our 

 bodies, and thus cause such diseases as malaria, yellow 

 fever, or sleeping sickness. 



27. Amoeba. — The name amoeba (a-me'ba) is given to 

 several different Protozoa, but all of them represent the 

 simplest form of life known to us. For this reason they 

 are always studied in biology. In order to describe cor- 

 rectly the structure of even so simple an animal as the 

 amoeba a few new words are necessary. 



28. Structure of Amoeba. — It is difficult for inexperienced 

 students to see the living amceba through the microscope, 

 because the whole cell 



has a faint, grayish ap- 

 pearance, and in a strong 

 light is transparent. 

 But if this grayish ap- 

 pearance of protoplasm 

 is once seen, it is always 

 remembered. 



The living amoeba is 

 continually changing 

 shape and pushing out 

 from the surface of its 

 body blunt, finger-like 

 projections of the proto- 

 plasm called pseudopodia 



(su-do-po'dl-a: Greek, pseudo, false; pod, root of pons. 

 foot), which give an irregular outline to the body (Figure 

 45). Sometimes the pseudopodia branch out, and there- 

 fore the scientific name Rhizopoda (ri-zop'o-da: Greek, 

 rhizos, root; pod, root of pous, foot) is the technical 

 name for all amoeba-like Protozoa. 



The amoeba sends out a pseudopodium, and gradually 



Figure 45. — Micro-photograph of an 

 Amceba. 



