=Form and Structure.=—The amœba looks so much like a clear drop of jelly that a beginner cannot be certain that he has found one until it moves. It is a speck of protoplasm (Fig. 9), with a clear outer layer, the _ectoplasm_; and a granular, internal part, the _endoplasm_. Is there a distinct line between them? (Fig. 10.) Note the central portion and the slender prolongations or _pseudopods_ (Greek, false feet). Does the endoplasm extend into the pseudopods? (Fig. 10.) Are the pseudopods arranged with any regularity? Sometimes it is possible to see a denser appearing portion, called the _nucleus_; also a clear space, the _contractile vacuole_ (Fig. 10). [Illustration: FIG. 11.—The same amœba seen at different times. ] =Movements.=—Sometimes while the pseudopods are being extended and contracted, the central portion remains in the same place (this is _motion_). Usually only one pseudopod is extended, and the body flows into it; this is _locomotion_ (Fig. 11). There is a new foot made for each step. =Feeding.=—If the amœba crawls near a food particle, the _pseudopod is pressed against it_, or a depression occurs (Fig. 12), and the particle is soon embedded in the endoplasm. Often a clear space called a _food vacuole_ is noticed around the food particle. This is the water that is taken in with the particle (Fig. 12). The water and the particle are soon absorbed and assimilated by the endoplasm. [Illustration: FIG. 12.—THE AMŒBA taking food. ] =Excretion.=—If a particle of sand or other indigestible matter is taken in, _it is left behind_ as the amœba moves on. There is a clear space called the _contractile vacuole_, which slowly contracts and disappears, then reappears and expands (Figs. 9 and 10). This possibly aids in excreting oxidized or useless material. =Circulation= in the amœba consists of the movement of its protoplasmic particles. It lacks special organs of circulation. =Feeling.=—_Jarring_ the glass slide seems to be felt, for it causes the activity of the amœba to vary. It does not take in for food every particle that it touches. This may be the beginning of _taste, based upon mere chemical affinity_. The pseudopods aid in feeling. =Reproduction.=—Sometimes an amœba is seen dividing into two parts. A _narrowing_ takes place in the middle; the _nucleus also divides_, a part going to each portion (Fig. 13). The mother amœba finally divides into two daughter amœbas. Sex is wanting. [Illustration: FIG. 13.—AMŒBA, Dividing. ]