Scanning electron microscopy of shell and mantle in the order Arcoida (Mollusca: Bivalvia)
Scanning electron microscopy of shell and mantle in the order Arcoida (Mollusca: Bivalvia)
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DOI：
10.5479/si.00810282.313
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
T. Waller
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文献类型：
--
作者：
T. Waller
Waller, Thomas R. Scanning Electron Microscopy of Shell and Mantle in the Order Arcoida (Mollusca: Bivalvia). Smithsonian Contributions to Zoology, number 313, 58 pages, 46 figures, 1 table, 1980.—Field investigations of living bivalves of the order Arcoida led to the rediscovery of a contradiction to the longstanding three-fold, three-function concept of bivalve mantle edges. In contrast to the simple secretory role usually ascribed to the outer fold, it was found that this fold is also photoreceptive, having both simple and compound eyes beneath the newly generated periostracum, and that it also may serve as a mantle curtain, controlling the flow of water into and out of the mantle cavity. Preserved specimens of Area zebra, Area imbricata, Barbatia cancellaria, and Glycymeris glycymeris were subsequently examined by scanning electron microscopy, with particular emphasis on mantle-shell relationships in specimens prepared by critical-point drying. These methods suggest two different modes of calcification: one inside the pallial line and characterized by high calcium mobility, the other outside the pallial line and closely controlled by a fibrous organic film that overlies the growth surface of the marginal shell band and is distinct from the periostracum. The pallial line in the Arcoida is primarily the result of morphological changes in the mantle epithelium and does not represent a continuous line of pallial-retractor insertions. Shell tubules, abundantly present in all arcoids examined, are formed by greatly elongated processes extending into the shell from the apical surfaces of epithelial cells inside the pallial line. These may chemically deter borers. The presence of two marginal mantle folds lateral to the periostracal groove as well as the presence of photoreceptors on one of these suggest that growth of the mantle is not by means of simple conveyorbelt-like proliferation of cells from a single zone. Rather, cell generation in the epithelia outside the pallial line is probably widely distributed, with many cells tending to maintain both their position and function during ontogeny. The peculiar arrangement of marginal mantle folds and the structure of compound eyes both probably result from very early divergence from a primitive bivalve and represent independently derived characters unique to the order Arcoida. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: The coral Montastrea cavernosa (Linnaeus). Library of Congress Cataloging in Publication Data Waller, Thomas R. Scanning electron microscopy of shell and mantle in the order Arcoida (Mollusca: Bivalvia) (Smithsonian contributions to zoology ; no. 313) Bibliography: p. 1. Arcoida—Anatomy. 2. Arcoida—Evolution. 3. Calcification. 4. Mollusks—Anatomy. 5. Mollusks—Evolution. I. Title. II. Series: Smithsonian Institution. Smithsonian contributions to zoology; no. 313. QLl.S54no. 313 [QL430.6] 591'.08s [594U1] 79-607786. Scanning Electron Microscopy of Shell and Mantle in the Order Arcoida (Mollusca: Bivalvia)
