What is a genus of nudibranchiate mollusks, found in the warmer latitudes, swimming in the open sea. These mollusks are beautifully colored with blue and silvery white called?

glaucus — A genus of nudibranchiate mollusks, found in the warmer latitudes, swimming in the open sea. These mollusks are beautifully colored with blue and silvery white. (Webster's 1913.)

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