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224 y^ inch in length, rather thin, but quite strong; surface glossy. 7 whorls. Suture well-impressed. Whorls in spire and upper third of body whorl with about 15 obliquely slanting, strong, rounded, axial ribs. Numerous spiral, incised lines are strongest on the base of the body whorl. Lower columella area with a small shield. Outer lip thickened within by about a dozen small white teeth. Color pinkish gray with indistinct motthngs of orange-brown. A common littoral to shallow-water species.

Figure 50. Small whelks of the Pacific coast, a, Amphissa versicolor Dall; b, A. Columbiana Dall; c, A. undata Cpr.; d, Searlesia dira Reeve. All X3. Amphissa columbiana Dall Alaska to San Pedro, California. Columbian Amphissa Figure 50b I inch in length, similar to versicolor, but characterized by its large size, numerous, weak, vertical, axial ribs (20 to 24 on the next to the last whorl, and missing on the last part of the last whorl), and by the low, rounded varix behind the outer lip. Color yellow-brown with indistinct mauve mottlings. Periostracum thin, yellowish brown. Moderately common in shallow water from Oregon to Alaska. Amphissa undata Carpenter Carpenter's Amphissa Figure 50c Monterey, California, to Lower California. Vs to y2 inch in length, similar to versicolor, especially in color, but with