(Zool.) Any one of numerous species of brachiopod shells belonging to the genus Lingula, and related genera. See Brachiopoda.
Lingula flags (Geol.), a group of strata in the lower Silurian or Cambrian system of Wales, in which some of the layers contain vast numbers of a species of Lingula.
... is the living 'Waldheimia' less embryonic, or more specialized; than the paleozoic 'Spirifer'; or the existing 'Rhynchonellae', 'Craniae', 'Discinae', 'Lingulae', than the Silurian species of the same genera? In what sense can 'Loligo' or 'Spirula' be said to be more specialized, or less embryonic, than 'Belemnites'; or the modern species of Lamellibranch and Gasteropod genera, than the Silurian species ... — Geological Contemporaneity and Persistent Types of Life • Thomas H. Huxley
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