PATELLA, or LIMPET, a genus of insects belonging to the order of vermes tellacea; the animal being of the snail kind. The shells are of that class which is called univexosa; they have no costae, and are in the form of little pointed cones. They are always attached to some hard body. Their summit is sometimes acute, sometimes obtuse, flattened, turned back, or perforated. The rock or other hard body to which they are always found adhering, serves as a kind of second or under shell to preserve them from injury; and for this reason Aldrovandus and Rondelet have classed them among the bivalves; but in this error they have not been followed by any other writer. Fabius
Columna distinguishes four sorts of the lepas or limpets: lepas vulgaris, a sort very common at Naples, of an oval figure and ash-colour. lepas major exotica, which comes from Spain, the shell is hard, thick, and ribbed in angles, and the rim is denticulated. The lepas agrea, or sylvestris, which is a small shell, irregularly oval, of an ash colour, marked with radii and zones crossing each other, and perforated at the top by an aperture which serves the fish for a vent. And the patella regalis, quia regis mensa sit digna; this is of a mother-of-pearl colour within, and is ribbed and perforated in many places: these shells have been found on the back of the sea-tortoise, or turtle, and on a large pinna marina. The distinguishing mark or characteristic of the lepas is to have but one convex shell, which adheres by its rim to a rock, or some other hard substance. There are 36 species of this genus, which are principally distinguished by peculiarities in their shells. Of some of these shells we have given engravings in Plate CCCLXXXII. of which we add the following description:
The limpet marked 1. has large yellow furrows and ridges from the centre to the circumference, which is indented; the eye is perfectly white, and shaped like a nipple.
That marked 2. is perfectly smooth, but radiated with brown streaks, and perforated in the summit.
Fig. 3. is ribbed, and indented at the circumference; its coat is spotted with brown, in a zig-zag form, and its eye is of a ruby colour.
Fig. 4. is a small brown shell, the ribs or striae of which are armed with small white points.
Fig. 5. is striated with radii, reaching from the eye to the circumference, which are crossed by other streaks nearly parallel to the circumference; it is of the usual colour, and its eye is perforated.
Fig. 6. This is white, shaped something like an hand-bell, and has within a protuberance somewhat resembling a clapper.
Fig. 7. is a seven-sided limpet, divided at each angle by ridges from the summit, which form a star on a white ground, variegated with black spots.
Fig. 8. is a small ribbed shell, of a brown colour, and rough; it has a chamber, and a beak-fashioned eye placed at one of its extremities.
Fig. 9. is the finest shell of this species: its size, the fine mother-of-pearl colour on the inside, and the beauty of its red spots without, which have the appearance of tortoise-shell, give it the pre-eminence over all others. It is called the Tortoise shell buckler.
The wild limpet, or patella fera, is a name very improperly applied by Rondelitus and Aldrovandus to the aurea marina, or concha veneris, which certainly is not of the patella kind.