Parts of The Shell
The terminology used to describe the shells of gastropods includes:
- Aperture: the opening of the shell
- Lip = peristome: the margin of the aperture
- Apex: the smallest few whorls of the shell
- Body whorl: the largest whorl in which the main part of the visceral mass of the mollusk is found
- Columella: the "little column" at the axis of revolution of the shell
- Operculum: the "trapdoor" of the shell
- Parietal callus: a ridge on the inner lip of the aperture in certain gastropods
- Periostracum: a thin layer of organic "skin" which forms the outer layer of the shell of many species
- Peristome: the part of the shell that is right around the aperture
- Plait: folds on the columella.
- Protoconch: the nuclear whorls; the larval shell, often remains in position even on an adult shell
- Sculpture: ornamentation on the outer surface of a shell
- Lira: one kind of shell sculpture
- Siphonal canal: an extension of the aperture in certain gastropods
- Spire: the part of the shell above the body whorl.
- Suture: The junction between whorls of most gastropods
- Teleoconch : the entire shell without the protoconch; the postnuclear whorls.
- Umbilicus: in shells where the whorls move apart as they grow, on the underside of the shell there is a deep depression reaching up towards the spire; this is the umbilicus
- Varix: on some mollusk shells, spaced raised and thickened vertical ribs mark the end of a period of rapid growth; these are varices
- Whorl: each one of the complete rotations of the shell spiral
Read more about this topic: Gastropod Shell
Famous quotes containing the words parts of, parts and/or shell:
“Three parts of him
Is ours already, and the man entire
Upon the next encounter yields him ours.”
—William Shakespeare (1564–1616)
“The Indian navigator naturally distinguishes by a name those parts of a stream where he has encountered quick water and forks, and again, the lakes and smooth water where he can rest his weary arms, since those are the most interesting and more arable parts to him.”
—Henry David Thoreau (1817–1862)
“We want some coat woven of elastic steel, stout as the first, and limber as the second. We want a ship in these billows we inhabit. An angular, dogmatic house would be rent to chips and splinters, in this storm of many elements. No, it must be tight, and fit to the form of man, to live at all; as a shell is the architecture of a house founded on the sea.”
—Ralph Waldo Emerson (1803–1882)