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Molluscous Animals; Including Shellfish Forming the Article 'mollusca' in the 7th Ed. of the Encyclopędia Britannica
Molluscous Animals Including Shellfish Forming the Article 'mollusca' in the 7th Ed of the Encyclopdia Britannica Author:John Fleming General Books publication date: 2009 Original publication date: 1837 Original Publisher: A. and C. Black Subjects: Mollusks Nature / Seashells Science / Life Sciences / Zoology / General Science / Life Sciences / Zoology / Invertebrates Notes: This is a black and white OCR reprint of the original. It has no illustrations and there m... more »ay be typos or missing text. When you buy the General Books edition of this book you get free trial access to Million-Books.com where you can select from more than a million books for free. Excerpt: CHAPTER III. SYSTEMATICAL DISTRIBUTION OF THE MOLLUSCA. The successful methodical disposition of molluscous animals, could not have been accomplished previous to labours similar to those of Cuvier and Lamark ; or until the shell and the contained animal were studied as connected objects. When thus contemplated, molluscous animals admit of arrangement into two great classes, or divisions, which may be distinguished from each other by well-defined characters. In the one, the presence of a head may be recognised, together with eyes, and even ears in some of the groups. In the other, containing animals much less perfect in their organization, there is no head, neither vestige of eyes or ears in any of the species. The former have been termed Mol- htsca Cephala, the latter Mollusca Acephala. This arrangement was first employed by Baron Cuvier, and afterwards by Lamark and other modern systematical writers. In the last work of the former naturalist, this method is departed from, and the six classes to which we have already referred, are constituted of equal rank, instead of being placed in subordination to the two primary divisions under which they can be suitably distributed. DIVISION I -- MOLLUSCA CEPHALA. Head distinct from the body, bearing the lips or jaws. The head, or the anterior part of the body on which Zoologists have bestowed that denomination, possesses more or less freedom of motion, and, on the dorsal aspect, supports ei...« less