Lower Florida Keys and the West Indies.
1⁄8 to 1⁄4 inch in length, moderately elongate, smoothish except for microscopic spiral grooves in some specimens. Color rose to brownish, sometimes whitish. Always with numerous small dots of pink, orange or a brownish color. Frequently with zigzag, axial bars of rose or brownish yellow. Often with irregular small spots or blotches of opaque-white. Umbilicus slit-like. Moderately common. T. concinna C. B. Adams is probably the same.
Tricolia tessellata Pot. and Mich. from the West Indies is somewhat the same, but it is characterized by distinct, revolving lines of orange or red that descend obliquely over the whorls. Common.
Plate 17r
Southeast Florida and the West Indies.
1⁄8 inch in length, spiral sculpture of numerous very small spiral cords, the largest being at the periphery of the whorl, thus giving the shell a slightly carinate shape. This carina is more pronounced in the early whorls and commonly bears a spiral row of tiny, white dots. Color variable, usually whitish gray with pink or brown axial mottlings and irregularly placed tiny dots of rose, yellow-brown or purplish brown. Umbilicus a mere chink. Operculum calcareous, convex, half smooth, the other half with fine, arched riblets. Common in shallow water among dead corals.
Crescent City, California, to the Gulf of California.
1⁄4 to 1⁄3 inch in length, resembling a moderately high-spired Littorina, but distinguished from that genus by its calcareous operculum. Shell smooth, in life covered by a thin gray-green, translucent periostracum. Characterized by the numerous, spiral lines of blackish green, red, brown or purplish which slant slightly downward, so that they are not parallel to the suture. Axial zigzag, wider bands are also present. Very abundant on eel-grass in shallow bays. Frequently washed ashore.
Genus Eulithidium Pilsbry 1898
Monterey to Lower California.
1⁄16 inch in length, depressed turbinate in shape, with 4 to 5 whorls. Char-
