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142 American Seash ells
and usually with a number of much smaller, variously sized threads. Color
orangish to yellowish white with darker, axial flammules. Moderately common
just offshore.
Turritella mariana Dall Maria's Turret-shell
Catalina Island to Panama Bay, Panama.
Plate 2 oh
1/4 to 1V2 inches in length, similar to cooperi, but with the whorls
slightly concave due to the more prominent, irregularly beaded spiral cords.
The aperture is not circular as in cooperi. Its color is usually much lighter.
Uncommon 20 to 40 fathoms.
Fatnily ARCHITECTONICIDAE
Genus Tovinia Gray 1842
Torinia bisulcata Orbigny Orbigny's Sun-dial
North Carolina to Florida and the Gulf of Mexico.
Plate 2 IX
^ to % inch in diameter, spire flattened, each whorl with 5 crowded
rows of neat, tiny, squarish beads. Periphery with a major, and below it a
minor, beaded cord. Base rounded and with about 7 wide cords bearing beads.
Umbilicus quite wide and very deep. Nuclear whorl glassy-white. Color of
shell dull gray to dull cream. Operculum solid-conic, chitinous. Uncommon
from 15 to 200 fathoms on mud bottom.
Torinia cylindrica Gmelin Cylinder Sun-dial
Lower Florida Keys and the West Indies.
% inch in length, equally wide; spire high; umbilicus narrow, round,
very deep, bordered inside with 3 spiral, beaded cords. Columella with 4
small, depressed, spiral lines. Top of whorls with 4 spiral cords of closely
packed, small beads. Color dark-gray to reddish brown with a cream base
and with white spots on the periphery. Uncommon at low tide.
Genus Architectonica Roding 1798
Architectonica nobilis Roding Common Sun-dial
Plate 4m
North Carolina to Florida, Texas and the West Indies.
I to 2 inches in diameter, heavy, cream with reddish brown spots which
are especially prominent just below the suture. Sculpture of 4 or 5 spiral
cords which are usually beaded. Umbilicus round, deep and bordered by a