PROTOPLASM OF AMCEB& 109 



have frequently observed this Amoeba, and for a long time 

 regarded it as a peculiar species, until I noticed one day 

 that a specimen, by throwing out a number of radiating 

 pseudopodia, passed into the typical form of A. radiosa. 

 Hence, I now have no doubt that it is only one of the 

 forms under which the very protean A. radiosa may appear. 



In one Amoeba, which had an elongated form during 

 movement, several finger-shaped pseudopodia of moderate 

 length are formed, as a rule, at the anterior end, and, pari 

 passu, with the movement of the Amoeba forward in a 

 straight line in the direction of its long axis, these pseudo- 

 podia travel backwards and are gradually retracted. Now 

 as long as the pseudopodia are at the anterior l end, they 

 appear, as a rule, homogeneous and structureless, but after 

 they have travelled backwards they become distinctly reti- 

 cular throughout, even up to the outermost margin. Hence 

 the same phenomenon would seem to be repeated here that 

 we observed in the retraction of the pseudopodia of Gromia 

 Dujardini. The pseudopodia of this Amoeba showed in the 

 preserved condition (picro-sulphuric-osmic mixture) a very 

 pretty reticular structure usually up to the extreme tips, 

 and the marginal layer of alveoli could at the same time be 

 seen with great distinctness (Plate II. Figs. 7 and 8). 



In the year 1878 I first drew attention to the fact that 

 A. Blattce, not uncommon in the end gut * of Blatta orientalis, 

 offers one of the best examples of fibrous protoplasm. In 

 this organism investigation in the living condition shows 

 the protoplasm to be very distinctly fibrous, and the fibre- 

 like appearances follow the direction of the movements. For 

 this point I will refer my readers to the description formerly 

 given by me. In recent times I have had the opportunity 

 of again observing this interesting Amoeba, but unfortunately 

 was unable to study it in detail. Still, I am able to complete 

 my former description in one point, namely, that the ap- 

 parent fibrillae are here also not disconnected, but united 

 into a network. If the Amoeba be followed in its move- 

 ments, it is easy to convince oneself that the fibrillar 

 appearance is only a consequence of the tensions caused by 



1 Proctodseum. 



