pseudopodia, which it would then retract, until the captured Brachionus
was safely within its abdominal cavity. On the slide there were several
grains of sand, but these the actinophrys passed by without notice.

I thought, at first, that this creature's attention was directed to its
prey by the movements of the latter, but further investigation showed me
that this was not the case.

After carefully rinsing the slide, I placed some alga spores (some of
which were ruptured, thus allowing the starch grains to escape) and some
minute crystals of uric acid upon it. Whenever the actinophrys touched a
starch grain with a pseudopod, the latter was at once retracted,
carrying the starch grain with it into the abdominal cavity of the
actinophryan; the uric acid crystals were always ignored.

I conclude from this experiment, that the actinophrys, which is
exceedingly low in the scale of animal life, recognizes food by taste,
or by some sense analogous to taste.

Many species of these little animals, however, are not as intelligent as
the Eichorn actinophrys; they very frequently take in inert and useless
substances, which, after a time, they get rid of by a process the
reverse of that which they use in "swallowing." By the latter process
they put _themselves_ on the outside of an object--in fact, they
surround it; by the former, they put the _object_ outside by allowing
it to escape through their bodies.

The sense of sight makes its appearance in animals quite low in the
scale, therefore the reader will pardon me if, while discussing this
sense, I prove to be a bit discursive. The subject is, withal, so very
interesting that it calls for a close and minute investigation.

One of the immutable laws of nature declares that animals which are
placed in new surroundings, not fatal to life, undergo certain changes
and modifications in their anatomical and physiological structures to
meet the exigencies demanded by such a modification of surroundings.
Thus, the flounder and his congeners, the turbot, the plaice, the sole,
etc., were, centuries and centuries ago, two-sided fishes, swimming
upright, after the manner of the perch, the bass, and the salmon, with
eyes arranged one on each side of the head. From upright fishes,
swimming, probably, close to the surface of the sea, they became
dwellers on its bottom, and, in order to hide themselves more
effectually from their enemies or their prey, they acquired the habit of
swimming wi