TROCHIDAE 113 



CalHostoma jujubinuni Gmelin Jubjube Top-shell 



Plate 3p 



Lower Florida Keys, the Bahamas and the West Indies. 



% to I /4 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 jujubinum has 

 a spire angle of about 50 degrees; the spiral threads on the whorls are weakly 

 beaded, and the umbilicus is almost closed. 



C. jiijiibimim tampaeiise Conrad (North Carolina to both sides of Flor- 

 ida 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. 



CalHostoma occidentale Mighels and Adams North Atlantic Top-shell 



Nova Scotia to Cape Cod, Massachusetts. Europe. 



^ 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. 



CalHostoma bairdi Verrill and Smith Baird's Top-shell 



Plate 3—0 



Massachusetts to North Carolina (and to Florida). 



1 to iVi 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 % 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 Dall is a form of this species whose umbilicus is half open. 



CalHostoma tricolor Gabb Three-colored Top-shell 



Figure 330 

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



