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Show SECOND GREAT DIVISION OF THE ANIMAL KINGDOM. ANIMALIA MOLLUSCA(!). The Mol1usca have neither an articulated skeleton nor a vertebral canal. Their nervous system is not united in a spinal marrow, but merely in a certain number of medullary masses dispersed in different points of the body, the chief of which, termed the brain, is situated transversely on the resophagus, and envelopes it with a nervous collar. Their organs of motion and of the sensations have not the same uniformity as to num- (1) That portion of the Baron's work which relates to the M:ollusca, and with which he commences the third volume of his last edition, is preceded by a few re· marks in the shape or a preface. As I have replaced this division, as well as that ofthe Zoophytes, in their proper situation, it is impossible to give that preface without creating an awkward break in the series. Besides this, it contains but little of moment. The author merely states the reasons which delayed the publication of the third volume for along time aftcrthe appearance of the fourth; among the most prominent of which were the number of changes in the genera, and in the distribution of species, he was compelled to make by recent discoveries. He also acknowledges his obligations to the works of the late lamented M. de Lamarck, and those of MM. de Blain ville, Savigny, Ferrussac, Des Hayes, D'Orbigny, Rudolphi, Bremser, Otto, Lcuckart, Chamisso, Eisenhardt, Rang, Sowerby, Charles Desmoulins, Quoy and Gaymard, Delle Chiaje, Defrance, Deslonchamp, Audouin, Milne Edwards, ~uges, Moquin Tandon, Morren, Ranzani, and othe1· savans whom he names in dt~erent places. He concludes by regretting that he had not received in time certam very recent works, which would have supplied him with valuable materials, particularly the Sy,t . .!lcalepk., Berlin, 1829, 4to, of M. Eschholtz, and the article ~phyte" of the Diet. des Sc. Nat., of M. de Blain ville, which was not then pub lished. .IJ.m. Ed. |