Page:American Seashells (1954).djvu/210

160 Yi inch or less in length, slightly fusiform with very slightly convex sides to the spire. Suture almost impossible to see. Color glossy yellow-brown with 2 rows of glassy, whitish, rounded beads. A third much weaker row of beads, or an additional spiral thread, may appear in the last 2 or 3 whorls. Axial threads connecting the beads are weak and form small pits. Fairly common under stones along the low-tide zone. Family JANTHINIDAE Genus Janth'ma Roding 1798 Subgenus Janthina s. str. Janthina janthina Linne Common Purple Sea-snail Plate 4) Pelagic in warm waters; both coasts of the United States. I to 1/4 inches in diameter. Whorls slightly angular. Two-toned, with purplish white above and deep purplish violet below. Outer Hp very slightly sinuate. Common after certain easterly blows along the south- eastern United States, especially from April to May. This is /. fragilis Lamarck. Subgenus Violetta Tredale 1929 Janthina globosa Swainson Globe Purple Sea-snail Plate 4k Cast ashore along both coasts of the United States. /4 to % inch in diameter. Whorls globose, well-rounded. Color violet throughout. Outer lip very slightly sinuate. Not very common. Subgenus Jodina Morch i860 Janthina exigua Lamarck Dwarf Purple Sea-snail Plate 4I Cast ashore in most warm seas. % inch in length. Whorls slightly flattened from above. Outer lip with a prominent notch. Light-violet, banded at the suture. Fairly common. /. bifida Nuttall is probably this species. NOTE Superfamily PYRAMIDELLACEA The families Pyrafiiidellidae, Aclididae, Eulimidae, Styliferidae and Efitoconchidae, most of which are small parasitic gastropods, have in the past been placed here among the prosobranchs, but are now considered to