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218 axial ribs, except for a rather strong, rounded varix behind the outer hp. Last whorl with about a dozen or so Hght-brown, spotted, spiral threads over a background of light yellowish gray. 3 to 5 fairly large teeth on the inside of the outer lip, Siphonal canal short, sealed over in adults. Periostracum thin, fuzzy, grayish with mauve-brown undertones. Interior of aperture light mauve-brown, usually with a whitish, spiral band on the middle of the body whorl. O. stearTisi Hemphill is the same. Very common in rocky rubble and on wharf pilings. Ocenebra circumtexta Stearns Circled Dwarf Triton Figure 49b Moss Beach, California, to Lower California. % to I inch in length, spire V^ the length of the shell. Characterized by very strong, rough spiral cords (15 on the body whorl, 6 on the whorls above). Under a lens the cords are seen to consist of arched, crowded, raised axial lamellae. The cords are often cream-white with the interspaces black- brown. Axial ribs wide, low, rounded and 7 to 9 per whorl. Some specimens are banded or have large, red-brown spots. A white form of this species was unnecessarily named citrica Dall. A very abundant species on rocks at low tide to 30 fathoms. Ocenebra poulsoni Carpenter Poulson's Dwarf Triton Plate 24k Santa Barbara, California, to Lower California. 1 % to 2 inches in length; a sturdy shell with a semi-gloss finish. 8 to 9 nodulated, rounded axial ribs per whorl crossed by numerous very fine, incised spiral lines and 4 or 5 larger, rounded, raised spiral cords. The latter make nodules on the ribs. Siphonal canal narrowly open. Periostracum thin, grayish or brownish and smoothish. When the periostracum is absent, the shell is glossy-white with numerous, fine spiral lines of dark- to yellow- brown. Aperture white. An exceedingly common species found in nearly every region on rocks and wharf pilings. Genus Pterorytis Conrad 1862 Pterorytis foliata Gmelin Foliated Thorn Purpura Plate 24h Alaska to San Pedro, California. 2 to 3 inches in length, with 3 large, thin, foliaceous varices per whorl which are finely fimbriated on the anterior side. Numerous spiral cords are rather prominent and of various sizes. Siphonal canal closed, its anterior tip turned up and to the right. Base of outer lip with a moderately strong spine.