1⁄3 inch in diameter, strong, opaque-white, depressed, 4 whorls. Top of whorls rounded, slightly concave just below the fine suture; bearing 5 or 6 major, smooth, spiral threads on top with numerous, much finer threads between. Periphery bordered above and below by a major cord. Umbilicus widely funnel-shaped, deep. Outer lip crenulate above. Not uncommon in shallow water. One of our largest American Vitrinellid species. Provisionally placed in this subgenus.
Genus Pseudomalaxis P. Fischer 1885
Virginia to southeast Florida and the West Indies.
3⁄8 inch in diameter, dull-white, planorboid, with a very flat spire and a wide concave, non-umbilicate base. Periphery of shell flat, bordered above and below by one or two spiral cords of small beads. Aperture squarish. Operculum round, multispiral with a chitinous pimple on the inside. A rare and choice collector’s item. Deep water. 70 fathoms.
Palm Beach and along the Lower Keys, Florida.
1.8 mm. in diameter, 3 to 4 whorls, semitranslucent-white to burnt sienna. Sculpture of fine, spiral striae and strong, widely spaced, radial ribs. Peripheral zone flattened or concave between 2 projecting nodulose keels. Under rocks. Moderately common to rare. This genus was formerly placed in the family Architectonicidae.
Genus Teinostoma H. and A. Adams 1854
Shells usually about 2 to 3 mm. in diameter, depressed, glossy, white, usually smooth, and with an umbilical callus. They are very distinctive little shells, but require a high-powered lens for their inspection. We have figured only one species, but have included a key from the work of Pilsbry and McGinty (1945) (see pl. 17y).
Key to the Florida Teinostoma
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