GENERIC CHARACTER.--See Pl. 75. * * * * * SPECIFIC CHARACTER. _N. testa subglobosa, mustelina concolore, obsolete rugata, fascia levata basin cingente; spira depressa, apice acuto; umbilico magno, aperto; columellae basi gracili, levata._ Shell sub-globose, uniform, fulvous-brown, obsoletely wrinkled, base with an elevated belt; spire depressed, the tip acute; umbilicus large, open; pillar termination slender, elevated, and central. * * * * * The elevated belt at the base affords an excellent distinction to this species. The specimen in my cabinet is the only one I have seen. Locality unknown. * * * * * NATICA sordida, _Brown Natica--middle figures._ * * * * * _N. testa subglobosa, fused, spira prominente; apertura intus fusco-purpurea; umbilico parvo, labio interiore paululum tecto; columella obsolete terminante._ Shell sub-globose, brown; spire prominent; aperture within purplish brown; umbilicus small, partially covered by the inner lip; pillar termination obsolete. * * * * * This Shell is both undescribed and apparently unfigured; the spire is more elevated than usual; the umbilicus small; and the termination of the pillar not seen: it is not uncommon, and is often much larger than here represented, but I am unacquainted with its locality. The little decision in the figures given by authors of these shells, renders it hazardous to quote them with certainty. * * * * * NATICA melastoma, _Black-mouthed Natica--lower figures._ * * * * * _N. testa depressa, fusca; spira complanata minima; ore intus atro-purpureo; umbilico magno, clauso labio interiore rufo._ Shell depressed, brown; spire flattened, very small; mouth within purplish black; umbilicus large, closed up by the inner lip, which is rufous. * * * * * In colour this bears a close resemblance to the last, but the shell is flattened beneath, and the spire very short and depressed; the umbilicus large, but, in general, quite closed up by the thickness of the pillar, united to the inner lip. In some specimens a narrow crescent-shaped groove is left on the outside margin. Its habitat is unknown. * * * * * Pl. 80 [Illustration] HALIOTIS Californiensis, _Small-holed Californian Ear-shell._ * * * * * GENERIC CHARACTER. _Testa univalvis, depressissima, lata, auriformis. Discus admodum perforatus. Spira minuta, depressa. Apertura testam magnitudine pene aequans, intus margaritifera._ Typus Genericus _H. Tuberculata_ Linn. &c.