142 American Se ash ells 



and usually with a number of much smaller, variously sized threads. Color 

 orangish to yellowish white with darker, axial flammules. Moderately com- 

 mon just offshore. 



Turritella mariana Dall Maria's Turret-shell 



Plate 2 oh 



Catalina Island to Panama Bay, Panama. 



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 T ovinia Gray 1842 



Torinia bisulcata Orbigny Orbigny's Sun-dial 



Plate 2 IX 

 North Carolina to Florida and the Gulf of Mexico. 



^ 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 



