Broadly subfusiform, nuclear whorls two, smooth, round; normal whorls seven, subangulated, concavely excavated above the angle; angle acutely tuberculated; below the angle the surface is ornamented by about twelve slightly oblique ribs, each rib ending in a tubercle at the upper angle; the whole surface is ornamented, besides these ribs, by small, closely placed, revolving ribs; color yellowish brown crossed by about a dozen brown revolving bands; these bands usually cover the larger of the concentric ribs; canal elongate, columella but slightly twisted; umbilicus obsolete; inner lip but slightly encrusted, bearing two sharp oblique folds; outer lip acute, simple.
Hab. One beach specimen, San Diego; another inhabited by a crab, Monterey, 10 fms., and a fragment much larger than the others, Monterey, 16 fms. All collected by Dr. Cooper.
No. 463, Mollusca, Survey Cabinet.
CALLIOSTOMA, Swains.
Zizyphinus, Gray.
C. tricolor, G.
C. t. conica, spira vix elevata; anfr. I nucleari, lævi; anfr. VI ad marginem truncatis, supra declivibus, infra planulatis; tota superficie confertim costata; costis minute granulatis; colore fulvo, lineis purpureis albo maculatis, spiraliter fasciato; apertura subquadrata, intus margaritacea; labio crasso, labro acuto; umbilico albo.
Long. ·45, lat. ·5, long. aper. ·19, lat. aper. ·24.
Shell conical, spire somewhat elevated, nuclear whorls smooth; other whorl sloping above, truncated on the margin, nearly flat below; surface marked by numerous, finely granulated, revolving ribs; color yellowish brown, banded by a variable number of spiral purple lines, interrupted by white spots; aperture subquadrate, nacreous within; inner lip heavy, outer lip and base acute, umbilicus white.