ectodermic

Their skin is merely a layer of ciliated ectodermic cells.

The Evolution of Man — Volume 2 Ernst Heinrich Philipp August Haeckel 1876

(Figure 1.73 A) leads to the formation of an eccentric cavity, the group of the darker entodermic cells (hy) remaining directly attached at one spot with the round enveloping stratum of the lighter ectodermic cells (ep).

The Evolution of Man — Volume 1 Ernst Heinrich Philipp August Haeckel 1876

The acoustic nerve is formed from ectodermic cells of the hind brain, and develops from the nervous structure that appears at its dorsal limit.

The Evolution of Man — Volume 2 Ernst Heinrich Philipp August Haeckel 1876

While the medullary groove is sinking in the middle line of the flat dorsal side of the oval embryo, and its parallel edges unite to form the ectodermic neural tube, the single chorda is formed directly underneath them, and on each side of this a parallel longitudinal fold, from the dorsal wall of the primitive gut.

The Evolution of Man — Volume 2 Ernst Heinrich Philipp August Haeckel 1876

The placenta is formed by the branches of the blood-vessels in the wall of the allantois growing into the hollow ectodermic tufts (villi) of the chorion, which run into corresponding depressions in the mucous membrane of the womb.

The Evolution of Man — Volume 2 Ernst Heinrich Philipp August Haeckel 1876

When we come to the higher Metazoa, in which the sensory functions and their organs are more advanced, we find a division of labour among the ectodermic cells.

The Evolution of Man — Volume 2 Ernst Heinrich Philipp August Haeckel 1876

The real wall of the vesicle enclosed by it consists of a simple layer of ectodermic cells (b), which are flattened by mutual pressure, and generally hexagonal; a light nucleus shines through their fine-grained protoplasm (Figure 1.108).

The Evolution of Man — Volume 1 Ernst Heinrich Philipp August Haeckel 1876

A section through the embryo in the hatched hen's egg towards the close of the first day of incubation shows in the middle of the dorsal surface a broad ectodermic medullary groove (Figure 1.92 Rf), and underneath the middle of the chorda (ch) and at each side of it a couple of broad mesodermic layers (sp).

The Evolution of Man — Volume 1 Ernst Heinrich Philipp August Haeckel 1876

Its globular blastula (Figure 1.45) consists of loosely-aggregated, yelk-filled entodermic cells or yelk-cells (dz) in the lower vegetal half; the upper, animal half encloses the hemispherical segmentation-cavity (fh), the curved roof of which is formed of two or three strata of small ectodermic cells.

The Evolution of Man — Volume 1 Ernst Heinrich Philipp August Haeckel 1876

(From Selenka.) a animal pole of the blastula, v vegetal pole, en mother-cell of the entoderm, ex ectodermic cells, s spermia, ib unnucleated yelk-balls

The Evolution of Man — Volume 1 Ernst Heinrich Philipp August Haeckel 1876