226 
POPULAR SCIENCE REVIEW. 
Amoeba, often travels about the endosarc. This is the nucleus, 
and it is made up of a less watery protoplasm than the rest of 
the Amoeba, and has a structureless membranous coat surround- 
ing it. Very often a clear space seems to appear and to move, 
but not in a manner resembling a contractile vesicle ; and if 
the focus of the object-glass be altered and taken a little from 
off the ordinary level, a pseudopodium will be found sticking 
up from the Amoeba and waving slowly in the water. It is the 
base of this fine projection which gives the appearance just 
noticed. As this Amoeba moves slowly along it catches and 
sticks by its small end to the minute things which come in the 
way. The large end ever in advance moves over every obstacle 
around and under it, but the most tempting food never sinks in 
or is caught by it. The pseudopodia become very active with 
growth and more and more disposed to be large and rounded 
(lobose), but neither they nor the sudden outrushes of diaphane 
catch or include anything. A little watching will show that 
the spot where things are taken in is close to the small extre- 
mity, and that very often one or more pseudopodia are projected 
there, so as to encircle a diatom or a green animalcule or a piece 
of alga, which is slowly pressed by them against the Amoeba 
and then sinks in. The prey becomes environed by a va- 
cuole, or is tumbled about in the endosarc amidst the jumble of 
things there. It would appear that the pseudopodia, besides 
their locomotive use, give warning of good things being about ; 
and if one of them should touch one of the long straggling 
threads of a Gromia, the whole Amoeba will often change its 
direction of movement, gradually slip under the house of its 
prey, and the Gromia falls into the endosarc at the usual spot 
for the inception of prey. Every now and then, as this Amoeba 
grows large, long lines appear to form on its surface (fig. 32), 
ridges of diaphane, which radiate more or less from the small 
to the large end ; and, moreover, occasional collections of en- 
dosarc and food crowd the small end, and some granules and bits 
of digested food escape. Should one of these Amcebas, with its 
pseudopodia well put forth, come within the range of the current 
of a Vorticella, it is whisked off the glass and whirled here and 
there until it comes with a bounce against the disturber (fig. 30.) 
Now, it is a very important fact, and one which lets a great deal 
of light into the nature of the Amoeban protoplasm, that no 
active or passive contraction should occur in it notwithstanding 
all this ill treatment. Just as when an animalcule with long* 
cilia comes rushing against an Amoeba, so, in the instance of 
the contact with the Vorticella, no evidence of contractility 
or irritability of the protoplasm is seen. 
Growing day by day, especially if there is abundance of uni- 
cellular algaceous food, this fine Amoeba finally has its en- 
