• Webster's Revised Unabridged Dictionary
    • n Nucula (Zoöl) A genus of small marine bivalve shells, having a pearly interior.
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Century Dictionary and Cyclopedia
    • n nucula A genus of acephalous or conchiferous mollusks, formerly referred to the Arcidæ or ark-shells, now made type of the family Nuculidæ. The size is small, and the shape resembles that of a beechnut, whence the name. There are about 70 living species, of which N. nucleus is typical, and numerous extinct ones, among which is N. cobboldiæ of the English crag.
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Webster's Revised Unabridged Dictionary
L., little nut, dim. of nux, nucis, a nut


In literature:

Remember Silurian Nautilus, Lingula and other Brachiopods, and Nucula, and amongst Echinoderms, the Silurian Asterias, etc.
"More Letters of Charles Darwin" by Charles Darwin
Nucula, a persistent type.
"More Letters of Charles Darwin Volume II" by Charles Darwin
Genres Pinna, Mytilus, Modiola, Nucula.
"Lamarck, the Founder of Evolution" by Alpheus Spring Packard