The most famous voyages of discovery were those lead by Captain Cook: there were three in total, and they took place over 12 years. They opened up many opportunities for nature study and naturalists were always on board throughout the expeditions. Unfortunately, however, conchology was not the main interest of any of the naturalists who sailed with Captain Cook and so there is little information to be gleaned about the mollusc and shell collecting that occurred. The shell excursions that are briefly mentioned were often made with the intention of collecting food, not shell specimens. However, many of the officers and seamen travelling with Cook brought back with them collections of shells and other "natural curiosities". But they were not doing this in the name of science; they were actually collecting such items to sell on their return. Such material was rare in Europe and a handsome profit could be made by selling it to dealers, who in turn sold on to wealthy collectors. Thomas Martyn was present at the return of the third Cook voyage and purchased two thirds of the shells available for the large sum of 400 guineas..."--University of Glasgow Special Collections website.