The Patella of Linnæus was divided by Lamarck into several distinct
genera, and now comprehends only such shells as are of a conical form,
with an imperforated summit. The anterior is that part to which the
summit inclines, and is always more narrow than the posterior part.
It derives its name from its resemblance to a little dish; the colour
and structure are various; some are smooth, others granulated, and many
are covered with elevated tuberculated ribs. The exterior is sometimes
of a pale fawn colour, and the interior of a bright pink; some have a
silvery hue, but the more general colour is bluish white or light brown.
This genus of shells is very numerous in all seas, but chiefly in hot
countries, where they are found of a larger size; they generally adhere
by their base to rocks, stones, and marine substances, from which it is
difficult to detach them.
Shell oval or circular, sub-conic; summit right or more or less recurved
anteriorly; the cavity simple, entire, more or less deep; the margin
complete and entirely horizontal; a narrow muscular impression.
Patella apicina.
P. granatina.
P. oculus.
P. barbara.
P. plicata.
P. laciniosa.
P. saccharina.
P. angulosa.
P. barbata.
P. longicosta.
P. spinifera.
P. aspera.
P. luteola.
P. pyramidata.
P. umbrella.
P. plumbea.
P. cærulea.
P. radians.
P. scutellaris.
P. viridula.
P. pectinata.
P. Galathea.
P. Safiana.
P. testudinaria.
P. cochlear.
P. compressa.
P. granularis.
P. decaurata.
P. Magellanica.
P. stellifera.
P. vulgata.
P. mammillaris.
P. lineata.
P. leucopleura.
P. notata.
P. Tarentina.
P. punctata.
P. puncturata.
P. Javanica.
P. tuberculifera.
P. miniata.
P. pellucida.
P. tricostata.
P. Australis.
P. cymbularia.
_P. vulgata._ The common Patella. Pl. 2, fig. 1.
Conic, summit obtuse and vertical; sometimes ribbed from the vertex to
the margin with divergent striæ, sometimes striated without ribs;
exterior dark brown or greenish, internal blue or purple radiations.
_P. compressa._ The compressed or flat-sided Patella. Pl. 2, fig. 2.
Oval, elongated, compressed on the sides, having the summit
sub-anterior, well marked, and curved; exterior fawn colour, interior of
a silvery hue.
_P. deaurata._ The golden red Patella. Pl. 2, fig. 3.
Sub-conic, summit more anterior, with a slight forward inclination;
colour yellowish red.
_P. cochlear._ The spoonlike Patella. Pl. 2, fig. 4.
Depressed, the summit hardly marked, and much more narrow in front than
behind; exterior brownish, interior light blue.
_P. scutellaris._ The buckler Patella. Pl. 2, fig. 5.
Depressed, summit sub-anterior, radiated from the summit to the margin;
brown colour, with a yellowish band parallel to the margin.
_P. pectinata._ The pectinated Patella. Pl. 2, fig. 6.
Oval, summit well marked and anteriorly inclined; ribbed from the summit
to the margin, which is slightly convex in the middle.
_P. cymbularia._ The cymbular Patella. Pl. 2, fig. 7.
Oval, thin, pearly, with a festooned margin; summit nearly marginal;
colour white, shaded with very light brown.
FAMILY III.
CALYPTRACEA. Seven genera.
The genera that constitute this family were separated by Lamarck from
the Patella of Linnæus.