AMOEBAE A 



209 



uninucleate bodies undergo fusion to form zygotes which de- 

 velop into multinucleate forms. Several species in fresh water. 

 Pelomyxa palustris Greef (Fig. 81, c). Inhabitants of stag- 

 nant water, creeping on the bottom in the mud. The amoeba 

 is large, often measuring 2 mm. or more in diameter. Sluggish 

 with one broad pseudopodium, by which the organism under- 







im^smmm 







c^:0 ' 







Fig. 81 a, b. Large and small individuals of Amoeba verrucosa. 

 X500 (After Leidy). 



c. Pelomyxa palustris. X80 (After Kiihn). 



d. P. villosa. X250 (After Leidy). 



goes rolling movement. The cytoplasm is not at all differenti- 

 ated into two regions. Numerous vacuoles and vesicular nuclei 

 present. The nuclei exceed one thousand in number. Various 

 inclusions often color the body brown to black and make it ap- 

 pear opaque. Symbiotic bacteria, Cladothrix pelomyxae Veley, 

 occur regularly. Some individuals extrude inclusions and en- 



