ClipArt ETC
"Fig. 26 - Parts of a Bill. a, side of upper mandible; b, culmen; c, nasal fossa; d, nostril; e(see below); f, gape, or whole commissural line; g, rictus; h, commissural point or angle of the mouth; i, ramus of under jaw; j, tomia of under mandible (the reference lines e should have been drawn to indicate the correct tomia of upper mandible):k, angle of gonys; l, gonys; m, side of under mandible; n, tips of mandibles." Elliot Coues, 1884

The Parts of a Bird Bill

"Fig. 26 - Parts of a Bill. a, side of upper mandible; b, culmen; c, nasal fossa; d, nostril; e(see…

"Chroicocephalus atricilla. Laughing Gull. Black-headed Gull. Bill longer than middle toe and claw, shorter than tarsus or head, moderately compressed, rather stout for this genus. Culmen and commissure both decurved and the end, the latter somewhat sinuate at the base. Gonys considerably concave in front of the angle, somewhat so between the angle and tip; although the angle id well defined, the tip of the bill is so decurved that a chord from tip to base does not touch it." Elliot Coues, 1884

Laughing Gull Bill

"Chroicocephalus atricilla. Laughing Gull. Black-headed Gull. Bill longer than middle toe and claw,…