Tridacna n. (Zool.) A genus of very large marine bivalve shells found on the coral reefs of the Indian and Pacific Oceans. One species (Tridacna gigas) often weighs four or five hundred pounds, and is sometimes used for baptismal fonts. Called also paw shell, and fountain shell.
... PINCTADA MAXIMA, while the black lip PINCTADA MARGARITIFERA occasionally yields fine and flawless specimens of a silvery lustre. One which is still lovingly remembered was of pale blue and wonderfully lighted. The commonest of the giant clams TRIDACNA GIGAS sometimes betrays evidence of past internal trouble by the presence of a concretion of porcelain whiteness and of porcellaneous texture, but such are not to be described as pearls and to ... — Tropic Days • E. J. Banfield
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