| Tonna | |
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| Five views of a shell of Tonna galea | |
| Scientific classification | |
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| Genus: | Tonna Brunnich, 1772 |
| Type species | |
| Buccinum galea | |
| Species | |
See text | |
| Synonyms [1] | |
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Tonna is a genus of large sea snails, marine gastropod molluscs in the family Tonnidae, the tun or cask shells. [1]
The thin shell is ventricose, inflated, generally globular, rarely oblong and encircled with ribs. The spire is short. The outer lip is crenulated and sometimes denticulated throughout its whole length. The oblong aperture is very large and emarginated inferiorly. The columella is channeled. There is no operculum.
The animal is very large, so as scarcely to be contained within its shell. The head is broad, swollen before, supporting two long, slender, obtuse, distant tentacles, dilated towards the base, where the eyes are situated. The mouth is large, muscular, strong and retractile. The respiratory tube is pretty stout. Its cavity is capacious, entirely open, provided with two branchiae placed on the left side, the larger of which, describes a pretty large semicircle. The trunk is cylindrical, very much developed, flexible, capable of being turned in every direction at the will of the animal, and of elongating itself in a remarkable manner. It is furnished internally with several rows of hooks. The foot is ovate, large, fleshy, bordering all parts of the shell. It is rounded, widened, lobed and dilated before, with a horizontal furrow. The posterior extremity has no trace of an. operculum. The generative organ of the male is very retractile. [2]
The genus Tonna comprehends a small number of species, some of which attain so remarkable a growth, that they are sometimes as large as a man's head. In fact the general appearance of the shell, of an inflated, thick-set form, calls up the image of a tun, whence is derived its generic name. Thus, the characters which make up these species are a form more or less inflated, girdled, and very globular. The spire is much shorter than the body whorl. This causes the size of the aperture, which almost always occupies two thirds of the length of the shell. [2]
The animals of the tuns are in general strongly colored, and painted with different tints which form bands and spottings upon their entire exterior. [2]
This marine species is cosmopolitan.
Species within the genus Tonna include:
Bulla is a genus of medium to large hermaphrodite sea snails, shelled marine opisthobranch gastropod molluscs. These herbivorous snails are in the suborder Cephalaspidea, headshield slugs, and the order Opisthobranchia.
Nucella, common name dog whelks or dog winkles, is a genus of small to medium-sized predatory sea snails, marine gastropod mollusks in the subfamily Ocenebrinae which is part of the large family Muricidae, the murex snails or rock snails.
Turritella is a genus of medium-sized sea snails with an operculum, marine gastropod mollusks in the family Turritellidae.
Scutus is a genus of large sea snails or limpets with the common name "shield shells". These are marine gastropod molluscs in the family Fissurellidae, the keyhole limpets and slit limpets.
Buccinum is a genus of medium-sized sea snails, marine gastropod molluscs in the family Buccinidae, the true whelks.
Trochus is a genus of medium-sized to large, top-shaped sea snails with an operculum and a pearly inside to their shells, marine gastropod molluscs in the family Trochidae, the top snails.
Thais, sometimes known by the common names dog winkles or rock shells, is a genus of medium to large predatory sea snails with an operculum, marine gastropod mollusks in the family Muricidae.
Tonna cumingi, common name Cuming's tun, is a species of very large sea snail, a tun snail, a marine gastropod mollusc in the family Tonnidae, the tuns.
Tonna dolium, common name the spotted tun, is a species of large sea snail or tun snail, a marine gastropod mollusc in the family Tonnidae, the tun shells.
Tonna galea, commonly known as the giant tun, is a species of marine gastropod mollusc in the family Tonnidae. This very large sea snail or tun snail is found in the North Atlantic Ocean as far as the coast of West Africa, in the Mediterranean Sea and the Caribbean Sea. The species was first described by Carl Linnaeus in 1758.
Tonna perdix, common name the partridge tun, is a species of very large sea snail, a marine gastropod mollusc in the family Tonnidae, the tun shells.
Bursa is a genus of large sea snails, marine gastropod molluscs in the family Bursidae, the frog snails or frog shells.
Janthina is a genus of small to medium-sized pelagic or planktonic sea snails, marine gastropod molluscs in the family Epitoniidae.
Lithopoma is a genus of medium-sized to large sea snails with a calcareous operculum, marine gastropod mollusks in the family Turbinidae, the turban snails.
Tonna allium, common name the costate tun, is a species of large sea snail, a marine gastropod mollusk in the family Tonnidae, the tun shells.
Tonna dunkeri is a species of large sea snail, a marine gastropod mollusk in the family Tonnidae, the tun shells.
Tonna sulcosa, common name banded tun, is a species of large sea snail, a marine gastropod mollusk in the family Tonnidae, the tun shells.
Tonna chinensis, common name : the China tun, is a species of large sea snail, a marine gastropod mollusk in the family Tonnidae, the tun shells.
Tonna variegata, commonly known as the variegated tun, is a species of marine gastropod mollusc in the family Tonnidae.
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