ClipArt ETC
"Bill averaging somewhat longer, about 1.90; culmen, commissure, and gonys nearly straight; upper mandible somewhat dilated toward the base along the cutting edges, and less feathered; gonydeal angle prominent. Bill consequently approaches that of the next species, in width and depth, but exaggerates the length and straightness of that of the last species." Elliot Coues, 1884

Californian Guillemot Bill

"Bill averaging somewhat longer, about 1.90; culmen, commissure, and gonys nearly straight; upper mandible…

"Lomvia arra. Thick-billed Guillemot. Arrie. Bill short, stout, wide, deep; culmen curved throughout; commissure decurved at end; gonys if anything concave in outline, the angle very protuberant; cutting edges of the upper mandible dilated and denuded toward the base, this bare turgid space flesh-colored in life, drying pale yellowish." Elliot Coues, 1884

Thick-billed Guillemot Bill

"Lomvia arra. Thick-billed Guillemot. Arrie. Bill short, stout, wide, deep; culmen curved throughout;…