What is (a) A distinct girdle or band of color; a raised spiral line as seen on certain univalve shells. (b) The clitellus of earthworms. (c) The base of the crown of a tooth called?

cingulum — (a) A distinct girdle or band of color; a raised spiral line as seen on certain univalve shells. (b) The clitellus of earthworms. (c) The base of the crown of a tooth. (Webster's 1913.)

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