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gnathoˈtheca
gnathoˈtheca n. 
/ˌnaθə(ʊ)ˈθiːkə/, /ˌneɪθoʊˈθikə/, /ˌnæθəˈθikə/, /ˌnæθoʊˈθikə/ the horny covering of the lower beak of a bird.
Brit. /ˌneɪθə(ʊ)ˈθiːkə/
, /ˌneɪθə(ʊ)ˈθiːkə//ˌnaθə(ʊ)ˈθiːkə/U.S. /ˌneɪθəˈθikə/
, /ˌneɪθəˈθikə//ˌneɪθoʊˈθikə//ˌnæθəˈθikə//ˌnæθoʊˈθikə/ΘΚΠ
the world > animals > birds > parts of or bird defined by > [noun] > beak or bill > upper or lower beak > part or covering of lower beak
gonys1836
interramicorn1866
ramicorn1866
gnathotheca1870
1870 J. G. Cooper & S. F. Baird Ornithol. (Geol. Surv. Calif.) I. 567 Gnathotheca, the covering of the lower jaw.
1889 Cent. Dict. Gnathotheca.
1890 E. Coues Handbk. Field & Gen. Ornithol. ii. iii. 151 The entire covering of both jaws together is called rhamphotheca..of the under, gnathotheca..but these terms are not much used.
1959 J. Van Tyne & A. J. Berger Fund. Ornithol. ii. 31 The oral cavity is bounded by the horny coverings of the upper (rhinotheca) and lower (gnathotheca) mandibles.
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