Abstract
THE Quarterly Journal of Microscopical Science for January 1896, contains but one article—on the development of Asterina gibbosa, by E. W. MacBride, Fellow of St. John's College, with plates 18–29. The investigations forming the subject of this memoir were commenced some years ago; the author at first intended to work out the development of the so-called heart, with its accompanying sinuses, in the Asterids, as he had previously done in the case of the Ophiurids. Coming to the conclusion, however, that our knowledge of the development of most of the organs in the Asterid body was very defective, he determined to thoroughly revise their whole history, embryonic and larval. This work has occupied his attention for the last two years, and as a result we have this carefully written memoir, which the author hopes may be found to place our knowledge of Asterid development on the same level as that to which our acquaintance with Crinoid ontogeny has been raised by the researches, among others, of Bury and Seeliger. The material was chiefly collected at the Naples Station. The memoir is prefixed by a statement of the methods of research adopted, and concludes with a chapter entitled “General Considerations,” in which two questions are asked: (1) What light does this history throw on the affinities of the Asterids with the other Echinoderms? and (2) Does it suggest any direction in which we may look to find the origin of the group Echinodermata? The answer given to the former is that the Asterids have an affinity with the Crinoids, and that they had a fixed ancestor; and to the latter, that assuming a free-swimming ancestor of Echinoderms (provisionally called Dipleurula), it and the Tornaria ancestor of Balanoglossus must have been closely allied. This further involves the assumption that the Asterids were thus allied to the Protochordata.
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Scientific Serials. Nature 53, 334 (1896). https://doi.org/10.1038/053334a0
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DOI: https://doi.org/10.1038/053334a0