Note 1 — Chapter IX · DEVELOPMENTAL HISTORY OF ENTOMOSTRACA, CIRRIPEDES, AND RHIZOCEPHALA.

If the Phyllopoda may be regarded as the nearest allies of the Trilobites, they would furnish, with Lepidosteus and Polypterus, Lepidosiren and Protopterus, a further example of the preservation in fresh waters of forms long since extinguished in the sea. The occurrence of the Artemiæ in supersaline water would at the same time show that they do not escape destruction by means of the fresh water, but in consequence of the less amount of competition in it.