"_Stomatella_ is also very pretty; the shells are pearly. _S. auricula_, from New Holland, has the appearance of a little _Haliòtis_. "_Stomatia_ is a small genus. [Sidenote: HALIOTIS. VERMETUS. SCALARIA.] "With the genus _Haliòtis_ you are already acquainted. The animal appears to be very elegantly formed, if the plate I have seen of it be correct. "There is a number of fine specimens in the British Museum. * * * * * "The family _Plicacea_ contains only, _Tornatella_ _Voluta_, chiefly. _Pyramidella._ "All the species have plaits, or folds, on the columella. The shells are marine and foreign in both genera. (Plate 9.) * * * * * "Our next family, _Scalariana_, contains the genera _Vermetus._ _Scalaria_ _Turbo_. _Delphinula_ _Turbo_. * * * * * "The single species of the first genus, _Vermetus lumbricalis_, inhabits the sea near to Senegal. The shell is tubular, thin, twisted spirally; it is fixed on marine substances by the end of its thin, pointed spire. The shells are usually found in groups. "The genus _Scalaria_ is one of the most elegant among univalve shells. The singularity of the numerous ribs renders the shells easily known from all other genera of turreted _Mollusca_. The aperture is nearly round, the whorls gibbous, or inflated with carinated ribs: the colour is usually pink or white. It is very costly. (Plate 9.) These shells are brought from the East Indies. "The fossil species are very elegant: they are found in the strata above the chalk. "Two other species are common, _S. communis_ and _S. lamellosa_. The first is a British species, and is called the _false Wentletrap_. [Sidenote: DELPHINULA. SOLARIUM.] "The shells of the genus _Delphinula_ are solid, thick, somewhat discoid, often armed with spines, without any apparent columella. The recent species inhabit the Indian Ocean. There are several fossil species of _Delphinula_. "The _Turbinacea_ family contains many genera, with which you will soon become familiar. I believe you are already acquainted with this shell, which, from the time it was first known to collectors, has always been celebrated for beauty. It is now called _Solarium perspectivum_. (Plate 9.) The large, spiral, crenated umbilicus is its great peculiarity. The French call the shell _Cadran_, _dial_. In its natural state the shell is covered with an epidermis. There are a few fossil species, one in the oölite of our own country. The English name is _staircase trochus_. * * * * * [Sidenote: ROTELLA. TROCHUS. TURBO.] "The genera of _Turbinacea_ are,