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. Hab. San Pedro, five alive on the sand shoal; and Half Moon Bay, beach; also San Diego. Dr. Cooper. Also fossil in the Post Pliocene, San Pedro. No. 602, Mollusca, Survey Cabinet. The brown lines are variable in number, the under side of one specimen showing two and of another six of these lines. The granulation of the ribs is arranged in the lines of growth. N. Gen. PTYCHOSTYLIS, G. Testa Calliostomati similis, conoidea; spira elevata; apertura subquadrata; columella antice truncata, plicis obliquis duabus induta, labro acuto, umbilico nullo. Shell resembling Calliostoma, Swains, (_Zizyphinus_, Gray,) conical not umbilicate, internally pearly, spire moderately elevated; aperture subquadrate; columella bearing two oblique folds, the lower of which ends abruptly at the end of the columella; outer lip and base acute, smooth or internally striate; operculum unknown. P. CAFFEA, G. T. conoidea, tenui; spira elevata; anfr. I nucleari, lævi, anfr. V ad marginem subangulatis, supra recte declivis, ultimo infra sub-planato; sutura valde impressa; tota superficie concentrice tuberculato costata; costis circitur XVIII ad ult. anfr.; epidermide flavida; apertura oblique sub-quadrata, intus albida. Long. ·55, lat. ·58, long. aper. ·26, lat. aper. ·28, ang. diverg. 58°.