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Updated: May 20, 2025
The acrita were the first forms of animal life upon earth, the starting point of that great branch of organization. The polypi vaginati, in the crustaceous covering of the living mass, and their more or less articulated structure, represent the annulosa. In the radiated forms of the rotifera, and the simple structure of the polypi rudes, we are reminded of the radiata.
In the same stone the claws of crabs, fragments of echini, and other signs of a neighbouring beach, are observed. Eunomia radiata, Lamouroux. Section transverse to the tubes. b. Vertical section, showing the radiation of the tubes. c.
In the primary division of the animal kingdom, we find the type in the radiata, not one of which lives out of water. In the vertebrata, it is in the fishes. In both of these, feet are totally wanting. Descending to the class mammalia, we have this type in the cetacea, which present a comparatively slight development of limbs.
The species, and even genera of all the early radiata and mollusks were exchanged for others long ago. Thus to find not only frequent additions to the previously existing forms, but frequent withdrawals of forms which had apparently become inappropriate a constant shifting as well as advance is a fact calculated very forcibly to arrest attention.
Moreover, it belongs, in point of organization, to one of the highest orders of organisms; not to the radiata, not to the mollusca, but to the highest type of the articulata, the nearest to the vertebrata.
Agassiz, for example, like Cuvier, and in opposition to the majority of the German and English zoologists, regards the Radiata as one of the great primary divisions of the Animal Kingdom, although no one knows anything about the significance of the radiate arrangement in the life of these animals, and notwithstanding that the radiate Echinodermata are produced from bilateral larvae.
In many large coal-fields we continue as much in the dark respecting the invertebrate air-breathers then living, as if the coal had been thrown down in mid-ocean. The early date of the carboniferous strata can not explain the enigma, because we know that while the land supported a luxuriant vegetation, the contemporaneous seas swarmed with life with Articulata, Mollusca, Radiata, and Fishes.
In the department of zoology, we see zoophytes, radiata, mollusca, articulata, existing for ages before there were any higher forms. The first step forward gives fishes, the humblest class of the vertebrata; and, moreover, the earliest fishes partake of the character of the next lowest sub-kingdom, the articulata.
In the animal kingdom, luminosity is confined, I believe, to the Invertebrata, and is especially common amongst the Radiata and Mollusca; it is also frequent in the Entromostracous Crustacea, and in various genera of most orders of insects. The weather continuing bad, and snow falling, the country people began to leave for their winter-quarters at Lamteng.
We have to search among the shales and clays and sandstones which enclose the coal-seams, and in these we find petrified specimens which enable us to build up in our mind pictures of the vegetable creation which formed the jungles and forests of these immensely remote ages, and which, densely packed together on the old forest floor of those days, is now apparent to us as coal. Annularia radiata.
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