Page:American Seashells (1954).djvu/131

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TROCHIDAE
113
Calliostoma jujubimum Gmelin
Jubjube Top-shell
Plate 3p

Lower Florida Keys, the Bahamas and the West Indies.

12 to 1+14 inches in length. Characterized by the deep, narrow, smooth-sided umbilicus which is bordered by a spiral, beaded thread, and by the swollen, rounded periphery of each whorl, which in the spire is located just above the suture. Color ranges from brownish cream to reddish and is often maculated with white splotches near the periphery. Typical jujubimum has a spire angle of about 50 degrees; the spiral threads on the whorls are weakly beaded, and the umbilicus is almost closed.

C. jujubimum tampaense Conrad (North Carolina to both sides of Florida to Yucatan) varies in spire angle from 50 to 65 degrees, is not always so swollen at its periphery, and has 9 to 10 well-beaded spiral threads between each suture.

Calliostoma occidentale Mighels and Adams
North Atlantic Top-shell

Nova Scotia to Cape Cod, Massachusetts. Europe.

12 inch in length. equally wide. Whorls convex and with 3 to 4 strong spiral cords, the 2 lower ones smooth, the upper one beaded. Color pearly-white. No umbilicus. Outer lip fragile. Moderately common from 10 to 365 fathoms.

Calliostoma bairdi Verrill and Smith
Baird’s Top-shell
Plate 3—o

Massachusetts to North Carolina (and to Florida).

1 to 1+14 inches in length, about as wide. Angle of Spire about 70 degrees. Sides of spire straight to slightly convex. Base rather flat. Periphery angular. Sculpture of 6 to 7 spiral rows of small, neat beads, with those on the top-most row being the largest. Suture difficult to find. No umbilicus. Color brownish cream with faint maculations of light reddish. Not uncommon from 43 to 250 fathoms.

C. bairdi psyche Dall (North Carolina to Key West, 30 to 130 fathoms) is usually 34 inch in length, slightly wider, with a spire angle of about 75 to 80 degrees, and the color is lighter and more pearly. Base with 3 or 4 spiral brown lines. It has a chink-like depression beside the umbilicus. Uncommon. C. subumbilicatum Ball is a form of this species whose umbilicus is half open.

Calliostoma tricolor Gabb
Three-colored Top-shell
Figure 33e

Moss Beach, California, to Cape San Lucas, Mexico.