Animal. With two conical tentacula, and the eyes at their base; branchiæ formed in a row under the anterior margin of the cavity, near the neck.
Shell. Obliquely conical, anteriorly recurved, apex bent, almost spiral; aperture rounded, elliptical, the anterior margin shortest, acute, slightly sinuated; the posterior largest and rounded. One elongated and arched muscular impression, situated under the posterior margin. Inhabits the seas of Europe. Nine species.
- Pileopsis intorta.
- P. subrufa.
- P. spirirostris.
- P. retortella.
- P. ungarica.
- P. mitula.
- P. pennata.
- P. squamæformis.
- P. depressa.
5. Genus Calyptrea. Pl. [X].
Animal. The same as preceding genus.
Shell. This genus derives its common name, “the Cup-and-Saucer Limpit,” by having in the interior cavity a cup-shaped appendage, which is sometimes vertical, and sometimes like a horse-shoe, with a muscular impression of variable form, vertex ending in a small volution; smooth, margin entire, very glossy within, and provided with a laminar plate. Inhabits the Chinese and S. American seas. Nine species.
- Calyptrea porcellana.
- C. equestris.
- C. fornicata.
- C. peziza.
- C. angulata.
- C. tecum-sinense.
- C. scutellata.
- C. poculum.
- · · · · ·
- C. striata.*
6. Genus Crepidula. Pl. [X].
Animal. Head anteriorly forked, having two conical tentacula, with the eyes placed at their exterior base; mouth simple, destitute of jaws, and situated in the bifurcation of the head; branchiæ with tufts and projecting from the branchial cavity; the mantle never bordering the shell; foot minute, orifice lateral.
Shell. Ovate, or oblong; the back almost always convex, concave beneath; the spire very much inclined towards the margin; the aperture partly closed by a horizontal lamina. Inhabits the American seas. Thirteen species.