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This poor little creature having dodged two boulders by a hairbreadth, got out by the westward corner and fled athwart the hill, with flapping rucksack and twinkling knicker-bockered legs, leaving a trail of Cretaceous echinoderms behind him; while young Caddies, satisfied with the destruction he had achieved, came striding out to fulfil his purpose in the world.
James Hall, Palaeontologist of New York, to the fact that these Palaeozoic rocks of the Appalachian chain, which are of such enormous density, where they are almost entirely of mechanical origin, thin out gradually as they are traced to the westward, where evidently the contemporaneous seas allowed organic rocks to be formed by corals, echinoderms, and encrinites in clearer water, and where, although the same successive periods are represented, the total mass of strata from the Silurian to the Carboniferous, instead of being 40,000 is only 4000 feet thick.
The kindly remembrance which you send me is evidence that my long silence has not seemed strange to you. . .It would be wasting words to tell you how I have been prevented, by the distractions of my life, always increasing with old age, from acknowledging the admirable things received from you, upon living and fossil fishes, echinoderms, and glaciers.
Now that the annelid-hypothesis is "dead and buried," and other attempts to derive the Vertebrates from Medusae, Echinoderms, or Molluscs, have been equally unsuccessful, there is only one hypothesis left to answer the question of the origin of the Vertebrates the hypothesis that I advanced thirty-six years ago and called the "chordonia-hypothesis."
I do not here allude to their primitive origin, but simply to the general fact that among radiates the embryos of the higher classes represent, in miniature, types of the lower classes, as, for instance, those of the echinoderms resemble the medusae, those of the medusae the polyps.
The comparison of the Acalephs with the Echinoderms is still easier, for they both have tubes; but in the latter the tubes are inclosed in walls of their own, instead of traversing the mass of the body, as in Acalephs, etc.
We call this layer the blastoderm, and the sphere itself the blastula, or embryonic vesicle. This interesting blastula is very important. The conversion of the morula into a hollow ball proceeds on the same lines originally in the most diverse stems as, for instance, in many of the zoophytes and worms, the ascidia, many of the echinoderms and molluscs, and in the amphioxus.
Besides these, however, the same ancient schists have yielded two genera of brachiopods, Orthis and Orbicula, a Pteropod of the genus Theca, and four echinoderms of the cystidean family.
The Globigerinae, Cyatholiths, Coccospheres, Discoliths in the one are absolutely identical with those in the other; there are identical, or closely analogous, species of Sponges, Echinoderms, and Brachiopods.
The collections here, therefore, were small; but a good haul was made with the trawl net, which gathered half-a-dozen species of echinoderms, some small fishes, and a number of shells. Fog detained the vessel in Eden Harbor till a late hour in the morning, but the afternoon was favorable for the passage through the English Narrows, the most contracted part of Smythe's Channel.
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