. The doctrine of descent and Darwinism. Evolution. PEDIGREE OF VERTEBRATE ANIMALS. 251 lutionary history of the individual. Only, if all verte- brate animals testified their family connection by agree- ing inter sc in the distribution of the germ as well as in the fundamentally important organs, the spinal cord and the vertebral column, this token of their descent from inferior animals, which is unconditionally demanded by the theory, seemed to be entirely wanting. In other words, it seemed that in all vertebrate animals the memory of their original derivation had been obliterated by curtaile
. The doctrine of descent and Darwinism. Evolution. PEDIGREE OF VERTEBRATE ANIMALS. 251 lutionary history of the individual. Only, if all verte- brate animals testified their family connection by agree- ing inter sc in the distribution of the germ as well as in the fundamentally important organs, the spinal cord and the vertebral column, this token of their descent from inferior animals, which is unconditionally demanded by the theory, seemed to be entirely wanting. In other words, it seemed that in all vertebrate animals the memory of their original derivation had been obliterated by curtailed development (comp. p. 211). Thus the case remained until Kowalewsky a few years ago studied the development of the lancelet (Amphioxus), the lowest vertebrate animal known, and showed that in this crea- ture the typical phenomena of vertebrate development. Fig. 22. Larva of the Lancelet after Kowalewsky. are preceded by the phases required by the theory. We have already made acquaintance with this form of development (p. 51, &c.), and we here again point out its profound significance. It is only when the Amphioxus has passed through the phase of the vibrating, sac-like. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Schmidt, Dr. (Eduard Oskar), 1823-1886. London, H. S. King & Co.
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