BIRDS OF NORTH AND MIDDLE AMERICA. 299 



Medium-sized to extremely small Coraciiform birds with the myo- 

 logical formula A, hypotarsiis simj^le, spina externa and spina interna 

 present (but short); palate feo-ithognathous (Micropodii) or schi- 

 zognathous (Trochili), humerus extremely short and manus relatively 

 very long; bill cither short and broadly triangular with gape deeply 

 cleft and nostrils opening vertically, near together, and nonopercu- 

 late (Micropodii) or long and slender with nostrils opening laterally 

 antl broadly operculate and tongue extensile (Trocliili). 



Basipterygoid processes absent (rudimentary in some Micropodii) ; 

 temporal fosste deep; end of mandible truncated; vomer absent or 

 rudimentary^ nares holorhinal, impervious; coracoids separated; 

 metasterniun usually entire and convex (truncate or emarginate, 

 with two foramina, in Macropterygidse), the carina sterna very high; 

 only the left carotid artery developed (except in Micropodii, part); 

 cseca absent; oil-gland (if present) nude; syrinx tracheal (Micropodii) 

 or tracheo-bronchial (Trochili); intestinal convolutions of type VI; 

 flexor tendons of type V or Va, the hallux connected mth the flexor 

 perforans digitorum; semitendinosus, accessory semitendinosus, acces- 

 sory femoro-caudal, and sterno-coracoideus muscles and biceps slip 

 absent, the femoro-caudal muscle present; tensor patagii brevis 

 peculiar, no tendon being developed and the fleshy belly running on 

 to a special tendon wliich springs from the lower end of the outer 

 surface of the humerus and is continued, parallel to the forearm, 

 along the radial margin of the manus. Spinal pteryla well defined 

 on neck, forked on upper back; lateral cervical pterylee present, 

 lateral cervical apterium absent; lateral cervical, nuchal, and spinal 

 apteria present; occipital apterium present (indistinct in Micropodii); 

 adult downs present (on apteria, only, in Trochili) ; aftershaft present; 

 wing-coverts nonoscinine (the inverted middle series wanting); sec- 

 ondaries 6-11; primaries 10, the tenth, ninth, and eighth (usually 

 the tenth) longest; the fifth cubital remex present (except in some 

 Micropodii); rectrices 10; alula of 0-3 feathers; rictal bristles absent; 

 skin of manus dark. Young nidicolous and gymnopsedic. 



KEY TO THE SUPERFAMILIES OF MACROCHIRES/'' 



a. Palate schizognathous; toes anisodactylous, the deep plantar tendons passerine; 

 ribs, 8 jmirs; cervical htemapophyses "U="; humero-coracoid groove or fossa 

 present; tibial bridge absent; flexor tendons of type Vc; syrinx tracheo-bronchial; 

 bill long and slender, the gape not deeply cleft; nostrils lateral, broadly oper- 

 culate; tongue extensile; secondaries 6-7; alular feathers 0-1; frontal apterium 

 present; femoral pteryloe small, connected with the dorsal pteryla; aftershaft 

 small (sometimes rudimentary or, apparently, wanting) Trochili (p. 300). 



aa. Palate aegithognathous; toes pamprodactylous, the deep plantar tendons cora- 

 ciine; ribs, 6-7 pairs; cervical hsemapophysis " =T" ; humero-coracoid groove or 



« Anatomical characters chiefly from Gadow in Bronn's Thier-Reich, Birds, Syst. 

 Theil, p. 83. 



