40 RISEN. [Vol. XVII. 



We see projections starting out just like the pseudopodia of 

 an amoeba, and I have no doubt that these projections must 

 actually be considered as true amoeboid projections, serving 

 the very same purpose as do the pseudopodia of the amoeba, 

 that is, as organs of locomotion and perhaps also of prehension. 

 Unless we assume the existence of a special organ for the 

 movement and propulsion of the archosomes and the accessory 

 centrosomes, their movements and migrations from one part of 

 the cell to the other are simply unaccountable. But if we 

 assume, as our observations warrant us in doing, that the 

 centrosphere is an organ for the propulsion of the archosome, 

 then these movements become easily explainable. This theory 

 is yet more affirmed by the fact that the centrosphere is amoe- 

 boid in almost every instance in which from its position we can 

 consider it to be in activity, and in the act of moving from 

 one place to another. On the contrary, when we have reaons 

 to expect the archosome to be at rest, we also find that the 

 centrosphere is globular or disc-shaped instead of amoeboid. 

 This holds good also in regard to the accessory archosomes, 

 though with them it is more difficult to determine when they 

 are at rest and when in activity. 



We are therefore, I think, justified in assuming that the 

 archosome, as well as the accessory archosomes, propel them- 

 selves from one place to another by means of the amoeboid 

 centrosphere, which sphere, when at rest, assumes a globular 

 form, but when in activity shows an amoeboid margin, or 

 pseudopodia. 



The position of the archosome is variable, according to the 

 stage of development of the cell. It may be said, as a rule, 

 that the archosome is situated either in the granosphere or in 

 the plasmosphere, when both these spheres are present. In 

 the prophases of the auxocyte, in which the two spheres attain 

 their highest development, the archosome is generally found in 

 the granosphere. It then generally possesses two centrioles which 

 are either surrounded by a common somosphere or are sufficiently 

 apart to have a separate somosphere for each centriole. 



The archosome seems to move around in the two cytoplasmic 

 spheres in a most independent manner, sometimes being found 



