Bulletin of the American Museum of Natural History Volume 9
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1897 edition. Excerpt: ... or less, and not open at the points, so as to connect with each other. Besides these there are longitudinal tubes of various sizes, traversing the entire length of the shell and opening on the surface of the visceral cavity of the valve, so that the living surface of the shell is occupied by these openings from just within the border of the shell to within a short distance of the central cavities. In one part of one individual there are six ranges of these tubes visible side by side radially, varying from an eighth of an inch in diameter to half an inch, some round, some oval, and others irregular in shape; on other parts of the same specimen there are only one, two or three ranges, one within the other, but all very irregularly placed. In D'Orbigny's figure of the generic type, Ca/rrimzlu boi.v.j'i, he shows four ranges of tubes, each varying in size from minute ones near the outer edge to very large ones bordering the visceral cavity. In our specimen they are entirely without order, either as to size or arrangement in their relations to the outside or inside of the thickness of the shell. All the intermediate substance of the shell is composed of minute capillary tubes, as in Caprinella, except that the tubes, although quite small, are only distantly septate, sometimes a centimeter distant and occasionally only half a millimeter apart. Only fragments of the natural surface of the visceral cavity have been observed; on these the longitudinal tubes are seen to open upon the surface as round or oval holes, having a raised rim, the intermediate portion being depressed slightly, and the entire surface covered by small pits representing the ends of the capillary tubes, which gives to the surface a beautifully punctate structure. This...
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- 13 Sep 2013
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