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The mollusc shell or mollusk shell is typically a calcareous exoskeleton which encloses, supports and protects the soft parts of an animal in the phylum Mollusca. In everyday language, mollusc shells are often simply known as "shells", or in the case of marine species, "seashells". The ancestral mollusc is thought to have had a shell, but this has subsequently been lost or reduced on some families, such as the squid, octopus, and some smaller groups such as the caudofoveata and solenogastres, and the highly derived Xenoturbella. Malacology, the scientific study of molluscs as living organisms, has a branch devoted to the study of shells, and this is called conchology - although these terms used to be, and to a minor extent still are, used interchangeably, even by scientists (this is more common in Europe). Within some species of molluscs there is often a surprising degree of variation in the exact shape, pattern, ornamentation, and color of the shell. ... Read more

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Academy of Natural Sciences.Natural science, Natural history, American, Philosophical Society, Botany, Herbarium, Entomology, Ichthyology , Malacology, Vertebrate paleontology, Invertebrate paleontology, Limnology , Biogeochemistry, Ecosystem model, Aquatic insects, Phycology, Alpha taxonomy. ... Read more

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This book an EXACT reproduction of the original book published before 1923. This IS NOT an OCR'd book with strange characters, introduced typographical errors, and jumbled words.This book may have occasional imperfections such as missing or blurred pages, poor pictures, errant marks, etc. that were either part of the original artifact, or were introduced by the scanning process. We believe this work is culturally important, and despite the imperfections, have elected to bring it back into print as part of our continuing commitment to the preservation of printed works worldwide. We appreciate your understanding of the imperfections in the preservation process, and hope you enjoy this valuable book. ... Read more