nimal or dermal layer (ectoblast), and into a
vegetative or intestinal layer (hypoblast). At the sixth stage, there
branched off the prothelmis, or worms, with the first formations of a
nervous system, the simplest organs of sense, the simplest organs for
secretion (kidneys) and generation (sexual organs), represented to-day by
the gliding worms or turbellaria; as the seventh stage, the soft worms, as
he called them at first--the blood worms, or coelomati, as he describes
them in his "Anthropogeny"--a purely hypothetical stage, on which a true
body-cavity and blood were formed; the eighth stage are the chorda-animals
with the beginning of a spinal rod, corresponding to the larva of the
ascidiae. At the ninth stage, called the skull-less animals (acrania), and
corresponding to the still living lancelet, we enter the series of the
vertebrates. The importance of the eighth and ninth stages for the theory,
we have already pointed out in our remarks upon Darwin, p. 43. The tenth
stage is formed by those low fishes in which the spinal rod is
differentiated into the skull--and the vertebral-column, called the
single-nostriled animals (monorrhini), and represented by the cyclostoma of
today (hag and lampreys). The eleventh stage is formed by the primaeval fish
or selachii (sharks); the twelfth by the mud fish, of which there still
live the protopterus in Africa, the lepidosiren in the tributaries of the
Amazon, and the ceratodus in the swamps of Southern {49} Australia. On the
thirteenth stage, there are the gilled amphibians (sozobranchia), proteus
and axolotl; on the fourteenth, the tailed amphibians (sozura), newt and
salamander; on the fifteenth, the purely hypothetical primaeval amniota or
protamnia (amnion is the name given to the chorion which surrounds the
germ-water and embryo of the three higher classes of vertebrates) on the
sixteenth, the primary mammals (promammalia), to which the present
monotremes (ornithorhynchus and echidna) stand nearest; on the seventeenth,
the pouched animals or marsupialia; on the eighteenth, the semi-apes or
prosimiae (loris and maki); on the nineteenth, the tailed apes, or menocerca
(nose-apes and slender-apes, or semnopithecus); on the twentieth, the
man-like apes (anthropoides) or tail-less catarrhini (gorilla, chimpanzee,
orang outang and gibbon). And now we come to twenty-one--ape-like men or
speechless primaeval men (alali)--of whom we are reminded to-day by the
deaf, and dumb, the cret