Conchology

Conchologists mainly deal with four molluscan orders: the gastropods (snails), bivalves (clams), Polyplacophora (chitons) and Scaphopoda (tusk shells).

Some groups, such as the sea slug nudibranchs, have lost their shells altogether, while in others it has been replaced by a protein support structure.

Scientific interest began to develop towards the end of the 17th century, and in 1681 The Jesuit priest Filippo Bonanni published the two-volume atlas Ricreazione dell'occhio et della mente nell'osservazione delle chiocciole ("Recreation of the eye and of the mind in the observation of molluscs"), the first treatise devoted entirely to mollusc shells.

[1] In 1692 Martin Lister published Historia Conchyliorum, a comprehensive conchological text with more than 1,000 engraved plates.

He suggested the categories "single shelled ones" (modern Polyplacophora, limpets, and abalone), "snails or whelks" (Gastropoda), and "two-shelled ones" (Bivalvia).

[4] Thomas Say wrote the fundamental work American Conchology, or Descriptions of the Shells of North America, Illustrated From Coloured Figures From Original Drawings, Executed from Nature in six volumes (1830–1834).

The Japanese emperor Hirohito also amassed a huge collection, and was a competent and respected amateur conchologist.

As of 2020[update] the world's largest assemblage of mollusc shells was held by the Smithsonian Institution, which has c. 1 million lots[6] representing perhaps 50,000 species.