otoconiumn.

1838 T. W. Jones in Todd's Cycl. Anat. & Physiol. II. 539/1 Breschet has proposed for the solid masses the name of otolithi..and for the pulverulent ones that of otoconia.

1857 Proc. Royal Soc. 1856–7 8 385 In Mollusca, as in Fishes, the auditory concretions present themselves in one of two forms, viz. solitary lapilli, usually named otolithes, or groups of small granules of a rounded oval or irregular shape, which have been designated by the term otoconia.

1881 St. G. Mivart Cat 301 Two sacs connected by a narrow bent tube and containing within them small crystals of carbonate of lime, called otoliths, or otoconia.

1934 Philos. Trans. (Royal Soc.) B. 224 285 The natural period of oscillation of even the tiniest model otoconium may theoretically be adjusted to suit any requirement.

1958 J. E. Morton Molluscs viii. 148 Embedded in the foot are simple otocysts with calcareous otoconia.

1992 N.Y. Times 1 Dec. c6/2 Contrary to an opinion sometimes expressed, people do not have rocks in their heads, although their inner ears do contain some microscopic grains of calcium carbonate called otoconia. Bones in the inner ear, not the otoconia, serve much the same function for humans as the otoliths do for fish.