BIRDS OF NORTH AND MIDDLE AMERICA. 703 



b. Claw of inner toe normal (not notably larger, more stro igly curved, or sharper 



than the claws of other toes); thigh-muscle formula ABX or AX; syrinx not 



peculiar; liver with lobes equal or the left lobe larger than the right; rectrices 



usually 12-14 (16-18 in Cerorhinca); no Qeshy rictal rosette. 



c. Mandibular rami densely covered for much the greater part with short velvety 



feathering, the anterior edge of the feathering forming an obli(|ue lino (convex 



anteriorly) from or near the gonydeal angle torjctiis; latero-frontal feathering 



also dense and velvety, advancing to or beyond anterior end of nostril and 



partly overhanging its upper margin ; rectrices usually 1 2 ( 14 in Pinguinus only ) . 



{Alcinse.) 



d. Bill very deep and very much compressed, transversely grooved laterally 



(in adults), the culmen very strongly curved, more or less arched; loral 



antia very much nearer to tomium than to culmen; tail graduated, the 



rectrices pointed. {Alcese.) 



e. Bill relatively larger and longer, the distance from anterior end of nostril 



to tip of maxilla greater than from same point to rictus; mandible with 



numerous transverse grooves (in adults); wings greatly reduced, unfitted 



for flight; rectrices 14 Pinguinus (p. 710). 



ee. Bill relatively smaller and shorter, the distance from anterior end of nostril 

 to tip of maxilla much less than from the same point to rictus; mandible 

 with not more than two grooves; wings well-developed, fitted for pro- 

 longed flight; rectrices 12 Alca (p. 713). 



(Id. Bill narrow, elongate-subconical, only moderately compressed, the culmen 

 nearly straight for most of its length or very gently curved from about 

 middle portion, without transverse grooves; loral antia about midway 

 between culmen and tomium or nearer the former; tail slightly rounded, 



the rectrices not pointed. ( Urise.) XJria (p. 717). 



cc. Mandibular rami feathered for less than greater part, the anterior edge of the 



feathering forming a more or less distinct angle or antia; latero-frontal 



feathering falling short of anterior end of nostril or else (in Synthliboramphus) 



the short and broad nasal operculum unfeathered, tarsus longer than middle 



toe without claw, and acrotarsium transversely scutellate. (Phcderinse.) 



d. Gonys much shorter than distance from its base to rictus; bill simple in form, 



small and slender, or compressed, without deciduous accessory pieces; 



latero-frontal feathering advancing to at least middle of nostril. 



e. Bill more elongated, the latero-frontal antia much nearer to rictus than to 



tip of maxilla, the culmen nearly straight to near tip, where abruptly 



decurved; mandibular rami mostly unfeathered, the malar antia forming 



a distinct median angle; base of culmen unfeathered to behind posterior 



end of nostril; nostril slit-like, in extreme lower edge of the large and 



well-defined nasal fossa; size larger (wing not less than 150 mm.). 



(Ceppheie.) Cepphus (p. 732). 



ee. Bill more abbreviated, the latero-frontal or frontal antia much nearer to 

 tip of maxilla than to culmen, the latter gently to rather strongly curved 

 from near base; mandibular rami mostly feathered, there being no dis- 

 tinct, if any, malar antia; base of culmen unfeathered only to slightly 

 behind anterior end of nostril; nostril broadly oval, pyriform, or triangu- 

 lar, near anterior end of the mostly feathered nasal fossa; size smaller 

 (wing not more than 145 mm.). 

 /. Acrotarsium reticulate; outer toe not longer than middle toe and inner 

 toe not longer than first two phalanges of middle toe; bill more slender, 

 its depth at anterior end of nostril less than length of gonys; mandibular 

 rami mostly feathered, the naked portion much shorter than gonye 

 ( Brachyramphese . ) 



