^L. irrorata.^ A solid, robust shell, which attains a length of about one inch. It is in many respects suggestive of /L. litorea/, its Northern relative, but the spire is higher, with straighter outlines, and the apex is acute. The surface is ornamented with closely set, revolving ribs; the sutures are indistinct; the lip is thin, though thickened just within; and the color is whitish to pale cinereous greenish, sometimes spotted with broken brownish lines. Within it is white, with a reddish tinge on the columella, and brownish spots on the edge of the lip. This species ranges from Maryland to Texas; its station is between tides. ^L. angulifera.^ As the last species resembles /L. litorea/, so this other common Southern form resembles a greatly developed and large /L. rudis/ of the smoother variety. It has a high-spired shell, with an acute black tip. It has about six whorls, which are variously decorated by wavy, oblique black lines and revolving black lines broken into series of dots and larger spots near the suture. The ground-color varies from yellow to purple. None of the colors are very vivid. Within it is yellowish-white. This species has a much thinner and more delicate shell than any of the littorinas thus far considered. It is common on the piling of wharves and in sheltered nooks everywhere [pg373] between tides. It is essentially a tropical species of very wide and extended range, but it does not occur north of St. Augustine. At Tampa it has been found in vast numbers. (Plate LXIX.) The California coast furnishes two more species of /Littorina/. Their station is among the rocks between tides, and their habits are quite the same as those of the east-coast species. ^L. scutulata.^ In this species the color is of various shades, generally dark gray, mottled with white spots. A good-sized specimen measures one half of an inch in length. The spire is high; the columella flattened, broad; the shell is purplish-white within the aperture. (Plate LXIX.) ^L. planaxis.^ Somewhat larger than the last; wider; with a lower spire; grayish in color, sometimes speckled with white; chest nut-brown within. The columella is remarkably flattened, and a portion of the whorl next bordering the columella is excavated as though eaten away by the animal. These two species are often found associated on the rocks. (Plate LXIX.) GENUS ^Lacuna^ [Illustration: /Lacuna vincta./]