Dolium
Collier's New Encyclopedia (1921)
the tun, a genus of gasteropodous mollusca, family Buccinide. The shell is ventricose, spirally furrowed, with a small spire and very large ape.ture, the outer-lip cremated, and no operculum; known species, 14 recent, from the Mediterranean, the India and China seas, and the Pacific. Fossil species from the Tertiary, if not even commencing with the chalk. DOLLAR [an adaptation of the German thaler, which is itself an "abbreviation of Joachimsthaler, a coin so called because first coined from silver obtained from mines in Joachimsthal (i. e., Joachim's dale), in Bohemia, about 1518; they were sometimes called Schlickenthaler, because first coined by the counts of Schlick, a favorite coin, found under different names in almost every part of the globe.] The following are the principal dollars in circulation: (1) A gold coin of the United States; weight, 25.8 grains; fineness, .900; now no longer coined in pieces of one dollar but in multiples of the standard. (2) A silver coin of the United States. (3) A silver coin current in Mexico; fineness, .900; weight, 27.067 grammes, or 417.7 grains. (4) The unit of value in Canada, represented by paper only, Canada having no coinage of its own. (5) The English name of a silver coin in circulation in many other countries, as Norway, Sweden, Denmark, etc. In many cases the name is different, thus, the Spanish dollar is also called piastre, or duro; that of Peru, the sol; that of Chile, the peso, etc. The value of a dollar is the unit employed in reckoning money in the United States. The sign $, now generally used to signify a dollar, is commonly supposed to date from the time of the celebrated Pillar dollar of Spain. This dollar was known as the Piece of Eight (meaning eight reals), and the curved portion of the sign is a rude representation of the figure 8. The two vertical strokes are thought to be emblematical of the Pillars of Hercules, which were stamped upon the coin itself.
What Has Changed in the Last Century
When Collier's wrote this in 1921 the tun shells were still filed under Dolium in the family "Buccinide." Both labels have since gone: the name Tonna, published by Brünnich in 1772, has priority over Lamarck's Dolium, so the animals are now Tonna, and they sit in their own family, the Tonnidae, not with the true whelks. Modern counts also run well above the "14 recent" species Collier's allowed, and the shells are known from tropical and warm seas worldwide rather than just the listed Mediterranean and Indo-Pacific waters. The genus name itself came from the Latin dolium, the big-bellied earthenware storage jar that survives in numbers at Pompeii and Ostia, and that meaning is unchanged.
Written for this edition, 2026.