MORPHOLOGY 



43 



While the pseudopodia formed by an individual are usually of 

 characteristic form and appearance, they may show an entirely 

 different appearance under different circumstances. According to 

 the often-quoted experiment of Verworn, limax amoebae change 

 into radiosa amoebae upon addition of potassium hydrate to the 

 water (Fig. 7). Mast has recently shown that when Amoeba 

 proteus or A. dubia is transferred into pure water, the amoeba 

 produced radiating pseudopodia, and when transferred to a salt 



Fig. 6. Portion of Actinosphaerium eichhorni, X800 (Kiihn). ar, 

 axial rod; cv, contractile vacuole; ec, ectoplasm; en, endoplasm; n, 

 nucleus. 



medium, it changed into monopodial form, which change, he was 

 inclined to attribute to the difference in the water contents of the 

 amoeba. In some cases during and after certain internal changes, 

 an amoeba may show conspicuous differences in pseudopodia 

 (Neresheimer). As was stated before, pseudopodia occur widely 

 in forms which are placed under classes other than Sarcodina 

 during a part of their life-cycle. Care, therefore, should be exer- 

 cised in using them for taxonomic consideration of the Protozoa. 

 Flagella. The flagellum is a filamentous extension of the cyto- 

 plasm and is ordinarily extremely fine and highly vibratile, so 



