Knowledge of the Amoebse. Ill 



was exceedingly suitable for the completion and elucidation of 

 the observations made on the latter. 



I had already completed my observations and made the 

 drawings which are here given before I could procure the 

 literature which showed that the form in question was nothing 

 else than Auerbach's Amoeha actinopliora. 



A comparison of the figures given by this naturalist with 

 mine shows how closely we are in agreement as to external 

 characters ; and that I have, notwithstanding, reproduced my 

 drawings is in order that they may illustrate the point in 

 which I differ from Auerbach, namely the behaviour of the 

 outer membranous cortical layer, which here especially interests 

 us. In accordance with this I also give the description in 

 such a manner that it may represent the observation as I then 

 made it, uninfluenced by any thing previously known. 



The first striking point was that here also the protoplasm 

 was distinctly surrounded by a double contour, and the animal 

 appeared as if covered by an envelope. 



The periphery was for the most part perfectly smooth, and 

 only at one point did the animal extend a larger or smaller 

 number of lobate pseudopodia. In this way the Amoeba ac- 

 quired delusively the appearance of a thalamophorous 

 Rhizopod, with a closely-fitting thin carapace, from the orifice 

 of which processes protruded. A glance at fig. 9 will explain 

 this better than a detailed description. In this condition the 

 protoplasm in the interior forms a tolerably compact mass, in 

 which there are a number of rather large strongly-refractive 

 granules. 



When the number of the pseudopodia is large, so that a 

 whole tuft of them protrudes at once (fig. 9) , we see nothing 

 of the cortical zone at their place of issue ; it is entirely dis- 

 placed. It is otherwise when only a few, say two or three, 

 processes are pushed forth. The relations of the marginal 

 layer are then quite distinctly visible, and we find that, just 

 as in A. tentaculata^ the cortex is pushed out into a cone, at 

 the apex of which the pseudopodium makes its way out. 

 Here, therefore, the double contour is also produced by a more 

 tenacious layer surrounding the animal, which must be pene- 

 trated by the protoplasmic processes before they can issue 

 (fig. 14). Even in the previously described form, however, 

 we saw that we have not to do with a persistent membranous 

 structure, but that during the flow of the animal the cortical 

 layer becomes amalgamated with the rest of the sarcode. 

 This is much more distinctly observable in Amoeba actino- 

 pliora. Thus all at once we see how, as the animal changes 

 its form, the pseudopodia are at the same time nearly all 



