AMEBOID MOVEMENT 107 



carry particles as do amebas and Oscillatoria, and move about 

 through the agency of this film. The film travels spirally around the 

 euglena as it does in Oscillatoria filaments. In at least two species 

 the film moves parallel to the spiral striations on the outer surface. 

 In one species no spiral striations could be detected, although 

 the film moved spirally. The species of euglenas in which these 

 movements were observed, were not identified. 



The character of the movement of the euglenas is very similar 

 to that of the diatoms excepting that most of the diatoms do not 

 revolve on their longitudinal axes. The movement of particles 

 on the surface film of euglenas is quite like that in Oscillatoria, 

 though it is only under exceptional circumstances that one can 

 see particles attached to the surface film. The movement of the 

 particles indicates that the surface film moves from the anterior 

 end toward the posterior end, but whether the "spine" is to be 

 included was not definitely determined. The degree of cohesive- 

 ness of the film is high, for locomotion is rapid, even if only a 

 small part of the posterior end is in contact with the substratum, 

 as when moving over an Oscillatoria filament. To one who has 

 seen the movements of the surface films of amebas, diatoms and 

 Oscillatorial filaments, the most reasonable conclusion seems to 

 be that the cause of locomotion in crawling euglenas is the same as 

 that in Oscillatoria and diatoms. 



Evidence contributing to this conclusion is found in the cir- 

 cumstance that crawling euglenas, diatoms and Oscillatoria 

 threads are much more refractory to galvanic currents than flagel- 

 late euglenas or other flagellates or ciliates : The electrical ap- 

 paratus at my disposal was rather crude, but I was unable to 

 find that I could influence the direction or character of move- 

 ment of Oscillatoria filaments, diatoms or crawling euglenas 

 without injuring the organisms. Currents which had produced 

 a marked effect on ciliates or flagellates produced no effect what- 

 ever on amebas, diatoms, Oscillatoria or crawling euglenas. Dia- 

 toms are particularly resistant to the effect of electrical currents. 



The general conclusion regarding the source of energy of the 

 moving surface films, whether found on amebas, diatoms, des- 

 mids, or crawling euglenas, is that all derive their motive power 

 from the energy in the superficial films of these organisms ; while 



