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Webster 1913 Edition
Sheathbill
Sheath′billˊ
,Noun.
(Zool.)
Either one of two species of birds composing the genus
Chionis
, and family Chionidae
, native of the islands of the Antarctic seas. ☞ They are related to the gulls and the plovers, but more nearly to the latter. The base of the bill is covered with a saddle-shaped horny sheath, and the toes are only slightly webbed. The plumage of both species is white.