36 
Amoeba Chironomi, Nov. Sp. 
motion may occur. These movements may be considered separately; 
in each case, the movements are brought about by the agency of 
pseudopodia. Pseudopodia are formed by the very rapid protrusion of 
the ectoplasm, and the process so formed remains clear and transparent 
for a short time, its shape being more or less conical, sometimes more 
of the nature of a filopodium than of a lobopodium (Figs. 11, 14). The 
richly granular endoplasm, which up till now has exhibited peripheral 
streaming movements, then flows forwards into the ectoplasmic process, 
but remains surrounded by a thin layer of hyaline protoplasm (Figs. 3, 
11). In continuous progression in one direction, the ectoplasm at the 
apex of the pseudopodium, under the forward pressure of the endo¬ 
plasm, extends laterally, and the rest of the body of the organism 
gradually flows into the swollen pseudopodium, and so an oval 
body is produced, the long axis of which is at right angles to the 
original pseudopodium (Figs. 6, 7). Almost as soon as this oval form 
has been assumed, a new process arises in relatively the same region of 
the body as did its predecessor. At first, the process is purely ecto¬ 
plasmic and conical; then inflowing of endoplasm occurs and finally the 
shape of the organism becomes oval again. So far as I could determine 
there was little or no interval between the assumption of the oval form 
and the formation of a new pseudopodium; that is, the formation of a 
new pseudopodium begins directly after the disappearance of the 
previous one. The short axis of the oval form was always the axis 
about a continuation of which the pseudopodium was produced. 
Reversal of the direction of movement is fairly common. It is 
brought about by the formation of a pseudopodium at the end of the 
organism opposite to that at which the pseudopodium for forward 
progression is produced (Figs. 1, 2 and 14,15). Frequently the organism 
begins to reverse its movement before the forwardly directed pseudo¬ 
podium is completely withdrawn. In other words, the ectoplasmic 
portion of the original pseudopodium may persist for some time, with 
the result that the organism is temporarily spindle-shaped, with a 
somewhat globular, richly granular body and a rather clear pseudopodium 
at either end (Figs. 2, 15). The ectoplasm of the original pseudo¬ 
podium is gradually withdrawn from the previously forwardly directed 
end, and then the streaming of the endoplasm into the second ecto¬ 
plasmic process initiates active movement in the reverse direction. 
In fresh preparations, I noticed that the Amoebae kept in the 
neighbourhood of the tissue of the gut wall and rarely migrated far 
from it. In unruptured intestines the Amoebae could be seen moving 
