Search results
Results from the WOW.Com Content Network
When the word "seashells" refers only to the shells of marine mollusks, then studying seashells is part of conchology.Conchologists or serious collectors who have a scientific bias are in general careful not to disturb living populations and habitats: even though they may collect a few live animals, most responsible collectors do not often over-collect or otherwise disturb ecosystems.
The larval shell may have a completely different mineralogy to the adult conch, perhaps formed from amorphous calcite as opposed to an aragonite adult conch. [ 2 ] In those shelled molluscs that have indeterminate growth , the shell grows steadily over the lifetime of the mollusc by the addition of calcium carbonate to the leading edge or opening.
The shells of surf clams show growth rings and can demonstrate changes in the environment of the individual. The shells are formed by calcification, as the clam deposits calcium carbonate into the shell via either diet or metabolism. Pausing of growth due to internal or external factors appear marked by dark lines of growth on the shell.
Tonna galea, commonly known as the giant tun, is a species of marine gastropod mollusc in the family Tonnidae (also known as the tun shells). 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.
A clam shell (species Spisula solidissima) at Sandy Hook, New Jersey. Clam is a common name for several kinds of bivalve mollusc.The word is often applied only to those that are edible and live as infauna, spending most of their lives halfway buried in the sand of the sea floor or riverbeds.
His most best-known works are American Seashells, Seashells of the World, and The Kingdom of the Seashell. John DuPont is also known for his extensive collection which he donated to the Delaware Museum of Natural History in 1984. The Japanese emperor Hirohito also amassed a huge collection, and was a competent and respected amateur conchologist.
The ABC sitcom originally starred Michael J. Fox, who left the show after four seasons following his Parkinson's diagnosis and was replaced by Charlie Sheen
The valves of the shell are made of either calcite (as with, e.g. oysters) or both calcite and aragonite, usually with the aragonite forming an inner layer, as is the case with the Pteriida which have this layer in the form of nacre or mother of pearl.