Page:American Seashells (1954).djvu/209

Rh cords or threads. Axial sculpture of weak, obsolete or sometimes strong, very tiny, rounded riblets. A. t. diegeiisis Bartsch is a strongly sculptured form of this species. Family TRIPHORIDAE Genus Triphora Blainville 1828 Shell left-handed (sinistral), very small, and slender. Aperture subcir- cular. Siphonal canal short, curved backward, slightly emarginate, upper part almost or completely closed. Posterior canal very slightly developed. Sculpture of spiral rows of neat beads, often joined by axial threads. Triphora nigrocincta C. B. Adams Black-lined Trifora Plate i9y Massachusetts to Florida, Texas and the West Indies. Vs ^o Vi inch in length, left-handed, with lo to 12 slightly convex whorls; dark chestnut-brown with 3 spiral rows of prominent, grayish, glossy beads. Darker band of black-brown is just below the suture. Aperture and columella brown. A common species found on seaweed at low tide. Some- times considered a subspecies of perversa from Europe. Triphora decorata C. B. Adams Mottled Trifora Plate 19ZZ Southeast Florida, the West Indies and Bermuda. ^ inch in length, left-handed, with about 20 flat-sided whorls which bear 3 spiral rows of large beads (28 per row per whorl). Color of shell cream to gray with large, irregular maculations of reddish brown. Moderately common from i to 40 fathoms. T. ornata Deshayes from the same area is very similar, but half as large, the spire slightly concave instead of being flat. Triphora pule hell a C. B. Adams Beautiful Trifora Plate 19Z Southeast Florida and the 'est Indies. %6 inch in length, left-handed, spire slightly convex; 15 whorls slightly convex, and with 3 spiral rows of beads which are joined axially and spirally by small, low, smooth threads. Suture well-indented. Upper third of whorl, including beads, colored light-brown, lower two thirds white. Uncommon in shallow water down to 56 fathoms. Triphora pedroajja Bartsch San Pedro Trifora Redondo Beach, California, to Lower California.