What is "cepphus grylle"

Guillemot \Guil"le*mot`\, n. [F.] (Zo["o]l.) One of several northern sea birds, allied to the auks. They have short legs, placed far back, and are expert divers and swimmers.

Note: The common guillemots, or murres, belong to the genus Uria (as U. troile); the black or foolish guillemot ( Cepphus grylle, formerly Uria grylle), is called also sea pigeon and eligny. See Murre.