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112 American Seash ells
Subfamily CALLIOSTOMATINAE
Genus Calliostoma Swainson 1840
Calliostoma euglyptum A. Adams Sculptured Top-shell
North CaroHna to Florida and Texas.
Plate 17W
% inch in length, equally wide. Angle of spire about 70 degrees. Sides
of whorls slightly concave. Periphery well-rounded. No umbilicus. Whorls
with 6 major, well-beaded, spiral cords between each of which is a much
smaller, weakly beaded thread. Color dull-rose, sometimes with axial flam-
mules of cream. Nucleus pink or, when worn, dark purple. Moderately
common in some localities from low tide mark to 3 2 fathoms.
Calliostoma zonamestum A. Adams Chocolate-lined Top-shell
Lower Florida Keys and the West Indies.
Plate 311
% to I inch in length, slightly wider. Angle of spire about 70 degrees.
Sides of whorls flat; periphery sharp; base flat. Umbilicus deep, smooth-sided,
white. Whorls characterized by 10 spiral, beaded threads between each of
which there is a dark-chocolate line. Base olive with about 5 to 6 fine, brown,
spiral lines. A very beautiful and moderately rare species much sought after
by collectors.
Calliostoma roseolujn Dall Dall's Rosy Top-shell
North Carolina to both sides of Florida and Yucatan.
% inch in length, % as wide. Angle of spire about 50 degrees. Sides of
whorls well-rounded, and with 8 to 9 crowded spiral rows of numerous neat
beads. Columella upright, strong, with a slight twist. Color of shell light
orange-tan to cream, often with arched splotches of darker color running
axially across the whorl. No umbilicus. Aperture pearly-rose. Uncommon
from 12 to 100 fathoms.
Calliostoma pulchrum C. B. Adams Beautiful Top-shell
North Carolina to Florida, the Gulf of Mexico, and the West Indies.
% inch in length, % as wide. Angle of spire about 50 degrees. Sides of
whorls straight. Characterized by a pair of strong, spiral cords just above the
suture which are white with distantly spaced red-brown dots. Rest of whorl
pearly-green with 6 to 7 very weak (or sometimes strong) beaded spiral
threads. Columella almost upright, its inner side rounded, pearly. No umbili-
cus. Moderately common from i to 40 fathoms.