may also appear in eastern Florida. It has been named floridana Reeve 1855, rotundata von Martens 1865 and sphaera Pilsbry 1931.
Genus Smaragdia Issel 1869
Plate 4h
Southeast Florida, the West Indies and Bermuda.
1⁄4 to 1⁄8 inch in length, glossy, smooth, pea-green, often with tiny chalk-white bars and rarely with purplish brown, narrow, zigzag bars. True viridis comes from the Mediterranean. Some workers separate our form as the subspecies viridemaris Maury 1917. N. weyssei Russell 1940 is a synonym.
Order Mesogastropoda
Superfamily Littorinacea
Family Lacunidae
Genus Lacuna Turton 1827
Rather fragile, smooth periwinkles characterized by a shelf-like columella and a chink-like umbilicus. Periostracum smooth, fairly thin and light-brown. Operculum paucispiral and corneous. Cold-water inhabitants, usually dredged in areas of kelp weed.
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Figure 36. Northern Lacunas. a, Lacuna carinata Gould, 1⁄2 inch (Pacific coast); b, Lacuna unifasciata Cpr., 1⁄2 inch (California); c to e, Lacuna vincta Turton, 3⁄8 inch (both coasts); c operculum showing reinforcing bar (dotted); d, animal showing the penis on the right side; e, radula (a single row greatly enlarged).
Plate 22p; figure 36c-e
Arctic Ocean to Rhode Island. Alaska to California.
1⁄4, to 3⁄8 inch in length, 4 to 5 whorls, resembling a Littorina, but characterized by its fairly thin, but strong, translucent shell, its shelf-like columella along side of which is a long, narrow, deep umbilical chink. Outer lip fragile.
