The vast increase in the number of species, either undescribed or published in miscellaneous works, and voyages; the difficulty of obtaining such works, or of naming species without them, and the confusion of Synonymes which has been the result, are facts which prove the importance of the present undertaking. The facilities enjoyed by the author, in having access to several of the most important collections; and obtaining the fullest information respecting the localities of subjects by those who have sought them in their native abodes, will, it is trusted, enable him to supply a generally acknowledged desideratum. He hopes to do this in such a manner as to fulfil the expectations of his friends, who may rest assured that neither pains nor expense will be spared to ensure the correctness, completeness, and beauty of the work. The plan of the work is as follows:--it will consist of a complete series of Monographs of Genera of Shells. All the species and varieties of each genus will be described and figured. The essential characters will be given in latin. The explanations and general information will be expressed in English. The figures of average sized shells will be reduced to half the real diameter; those of larger size will be still further reduced; and those of small size will be represented of the natural dimensions. The size of the book is Imperial octavo. The paper, printing, engraving and colouring of the best description. A part, containing several Monographs will appear every third month, or oftener if possible, the price of each part to depend upon the number of figures which it contains, at the rate of one penny for each figure. THE 2nd PART WILL APPEAR ON THE 1st OF AUGUST. * * * * * THE CONCHOLOGICAL ILLUSTRATIONS, _Or, figures of hitherto unfigured recent Shells, Part 1 to 200_, PRICE, 1S. 6D. EACH, May now be had with Indices complete. None of the Genera contained in this work will be given in the Thesaurus until all the other Genera are exhausted. * * * * * SOWERBY, NATURALIST. No. 50, GREAT RUSSELL STREET, BLOOMSBURY. * * * * * CORRECTIONS MADE TO PRINTED TEXT ANOMIA: "sub-equilateral" corrected from "sub-equilaternal" ARGONAUTA: "Cephalopoda" corrected from "Cepholopoda" ib. "the Argonaut is the testaceous part" corrected from "... Agonaut ..." HALIOTIS: "oblique" corrected from "obilque" POLYLEPAS: "lepas, rock." corrected from "lepas, Linn." RHINODOMUS: "No internal groove" corrected from "... grove" 65. "Panopæa Australis" corrected from "... Ausrtalis" Heading: "Fam. Brachiopoda" corrected from "... Brachipoda" End of the Project Gutenberg EBook of A Conchological Manual, by George Brettingham Sowerby