ce (protoplasma). Edward
von Benden, in his work upon _Gregarinae_, first clearly pointed out this
fact, that we must distinguish thoroughly between the plasson of cytods
and the protoplasm of cells.

An irrefutable proof that such single-celled primaeval animals like the
amoeba really existed as the direct ancestors of man, is furnished,
according to the fundamental law of biogeny, by the fact that the human
egg is nothing more than a simple cell.

The next step taken in advance is the division of the cell in
two;--there arise from the single germinal spot two new kernel specks,
and then, in like manner, out of the germinal vesicle two new
cell-kernels. The same process of cell-division now repeats itself
several times in succession, and the products of the division form a
perfect union. This organism may be called a community of _amoebae_
(synamoebae).

From the community of amoeba morula, now arose ciliated larvae. The
cells lying on the surface extended hair-like processes or fringes of
hair, which, by striking against the water, kept the whole body
rotating--the lanceolate animals or amphioxus were thus first produced.
Here we find from the synamoebae which crept about slowly at the bottom
of the Laurentian primeval ocean by means of movements like those of an
amoeba, that the newly-formed planaea by the vibrating movements of the
cilia, the entire multicellular body acquired a more rapid and stronger
motion, and passed over from the creeping to the swimming mode of
locomotion. The planaea consisted, then, of two kinds of cells--inner
ones like the amoebae, and external "ciliated cells." The ancestors of
man, which possessed the form value of the ciliated larva, is, of
course, extinct at the present day.

[Illustration: FIG. I.--The Norwegian Flimmer-ball (Magosphoera
Planula), swimming by means of its vibratile fringes; seen from the
surface.--_Haeckel._]

[Illustration: FIG. II.--The same in section. The pear-shaped cells are
seen bound together in the centre of the gelatinous sphere by a
thread-like process. Each cell contains both a kernel and a contractile
vesicle. (PLANAEA SERIES.)--_Haeckel._]

[Illustration: FIGS. III AND IV.--Represents GASTRAEA SERIES. The body
consists merely of a simple primitive intestine, the wall of which is
formed of two primary germ-layers.--_Haeckel._]

[Illustration: FIGS. I and II.--Represents the next higher stage
(Tubularia). Fig. I, a simple Gliding Worm (Rhabdocoe