Synopsis
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1864 edition. Excerpt: ... CHAPTER XVII. GENEAGENETIC PHENOMENA OF RADIATA. The three classes--Echinodermata (sea-urchins, &c), Acalephae (jelly-fish), and Polyps--which collectively constitute the sub-kingdom Radiata, require to be very fully treated, in order to give a detailed account of the varied and complex phenomena presented in their reproduction. Geneagenesis is seen here in all its phases; and as in many other instances, so in this one, the study of embryogeny, by disclosing unexpected results, put the history of these beings in an entirely new light, and modified received opinions in many particulars. We have spoken of the Hydra and Aurelia already, and we shall now mention some additional facts in support of this assertion. As an example, we shall select from the arborescent, plant-like polyps which cover our rocks and seaweeds, the pretty Campanularia geniculata, whose strange development has been so patiently watched by Lowen; but we shall now and then explain the results arrived at by the Swedish naturalist, f through the assistance of Steenstrup's writings and those of his followers. " Observations sur le DeVeloppement et les Metamorphoses des genres Campanulaire et Syncorne." This work, which was first published in Swedish, was afterwards translated into French and German.--Annales des Sciences naturellcs, 1811. t " Uber den Generationwechsel.". From the egg of this Campanularia there springs a ciliated larva, which attaches itself to a solid body, becomes flattened, and then resembles a little cake, which has a cavity hollowed in its substance. In the centre of this, granulations make their appearance, and gradually increase in size, elongate, and are converted into a straight hollow stem, which is soon covered by a transparent horny sheath. The...
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