M. E. Claparede on Actinophrys Sol. 287 



any point of its surface at pleasure. Thus, SiebolcVs assertion 

 that when the contractile vesicles are protruded the integument 

 retains sufl&cient elasticity to drive the nutritive fluid back into 

 the parenchyma, also falls to the ground, and we must endeavour 

 to explain this phaenomenon in another way. Perty indeed 

 states that in Actinophrys viridis he has distinguished a cap- 

 sule, perhaps only optically of a reddish colour, and its contents, 

 consisting of closely packed green globules. The capsule ap- 

 peared to him to be double, but the two laminse were united in 

 different places, so as to give it a waved appearance. He also 

 ascribes the same character to his A. brevipilis {brevicirrhis ?). 

 His figures, however, show that this notion has arisen from an 

 illusion. Actinophrys Sol often presents the same tuberculated 

 appearance, and Pcrty's supposed skin is nothing but the cor- 

 tical layer already mentioned. He would probably have adopted 

 a different opinion if he had seen the animal in the act of 

 taking nourishment. 



The entire mass of the body in Actinophrys appears to con- 

 sist of the same substance, — sai'code as Dujardin would call it. 

 This substance, which occurs in all Rhizopoda, looks like a tough 

 mucus or thick jelly. The radiating processes ai-e also composed 

 of the same material ; of this we may easily be convinced, if we 

 observe the animal when it is slowly extending or contracting 

 its processes, or when the latter are seen bending and fusing 

 together. I have never seen these processes become stiff, as 

 Perty states, so that other Infusoria could impale themselves 

 upon them, and I have no hesitation in regarding this as an 

 impossibility. It is nevertheless quite certain that small ani- 

 mals and plants remain adhering to them, for these rays are 

 true tentacles. Indeed their contact must have something very 

 unpleasant about it, for larger Infusoria, even such as Parame- 

 cium Aurelia, on coming accidentally within their reach, start 

 back with the greatest rapidity, sometimes even dragging the 

 Actinophrys, to which they have incautiously attached them- 

 selves, a considerable distance with them. 



Like Kolliker, therefore, we refer Actinophrys to the Rhizo- 

 poda, but we cannot adopt his views as to its constitution. Thus 

 he adopts Dujardin's sarcode without reservation, so that these 

 wonderful creatures would consist of a structureless body, a 

 homogeneous contractile substance without mouth, intestine, or 

 any other organ ; and finally, at least according to Kolliker, they 

 would be unicellular animals. I cannot, however, agree in the 

 least with this latter view. Actinophrys, Amoeba, Arcella, and the 

 other Rhizopoda, are entirely destitute of an integument ; the 

 cell-membrane is consequently deficient. I must equally deny 

 the existence of a nucleus in the naked Rhizopoda (at least in 



