Here I must observe, that the bottoms of the several species of this division conform in shape to the substances they adhere to, or grasp them in such a peculiar manner, as to render their situation secure from the violence of the element they live in. Another provision of nature for the security of these animals are the four opercula, which, upon their retreating into the great shell, they can draw to so close after them, as to secure themselves from outward danger.
[Fig. 7.] represents the Whale Barnacle, called Pediculus Ceti, just as it was cut off the whale’s lip, with the seven naked Barnacles with ears, already described. [Fig. 7.a] is the bottom of the shell. This has the appearance of the gills of a mushroom. All the spaces between these laminæ were filled with the blubber of the whale: by this means they adhere to the gristly skin of the fish. The narrow cavities between the branched laminæ are the places where the ligaments or tendons, that move the opercula, are inserted.
[Fig. 8.] is the Cup Barnacle, taken off an East India ship from Sumatra. The testaceous flat bottom of this was marked with the seams and lines of the sheathing, and with the rust of the nails. In one of these shells the animal is represented protruding his claws thro’ the opercula.
[Fig. 9.] is called the Bell-shaped Barnacle. This was taken off the bottom of a ship from Jamaica, and had its flat testaceous base marked as the former.
[Fig. 10.] This represents part of a most elegant specimen in the curious collection of Dr. John Fothergill. It is called the Tulip Barnacle, and very properly, as well from the shape of its shell, as the beautiful stripes of red mixt with white. It adheres to a piece of the true red coral, and was fished up near Leghorn, on the coast of Italy. It is not improbable, but that these groups of Barnacles, growing at the same time with the animals that formed the red coral, may have received an addition to their fine red colour from the coral.
[Fig. 11.] is a group of Barnacles of a conical form, composed of purplish tubes like small quills. [Fig. 11.a] represents one of the same, with a view of its base, from the collection of Mr. Peter Collinson, F.R.S. This was brought from the East Indies. The insides of these shells have the appearance of the spongy parts of bones.
[Fig. 12.] is called the Tortoise-wart Barnacle, being often found upon that animal. This shell is of a plano-convex shape, and looks like polished ivory. The divisions between the valves represent a star with six points. If these shells are put into soap lees, they will in a few hours separate into six pieces or valves, each shelly valve having two ears, like the scallop-shell: so that this species has its valves connected by membranes, instead of testaceous sutures, as most of the others have. [Fig. 12. a] represents the under part of the same shell.
[Fig. 13.] This shell is marked with six rays like a star, as the former; but is much deeper in proportion to its diameter. Several of this kind were found sticking to a crab, that was lately brought from the island of Nevis; from whence I have called it the American Crabs-wart.
[Fig. 14.] is called the Side-mouth Barnacle. This was found on the southern coast of Africa, near the Cape of Good Hope, where it adheres to a particular species of striated purple muscle. [Fig. 14.a] represents two of the opercula of this Barnacle remarkably horned. The shell of this is very thin; but its obliquity may probably be owing to its situation.
[Fig. 15.] This egg-shaped Barnacle with a small mouth is found in clusters sticking to the Buccinum tribe of shells in the West Indies.