BIRDS OF NORTH AND MIDDLE AMERICA 3 



raised high above the antitro chanter; pubis, when present, generally 

 closely approximated to ventral border of ischium. Ambiens and 

 femorocaudal muscles present; biceps sUp absent; expansor sccundari- 

 orum usually absent (present in Polyborus, Milvago, Falco, " Cerchneis," 

 Microhierax, and Harpy haliaetus) ; tensor patagii brevis simple; 

 pectoralis primus muscle divided into two layers (except in Milvago 

 and Dryotriorchis) ; peroneal muscles both present; glutacus I usually 

 absent, glutaeus II usually present; deep plantar tendons of type III 

 (except in Cathartae and Pandionidae) , the flexor hallucis dividing 

 into two parts at lower end of metatarsus, one part going to the hallux, 

 the other blending with the branch of the flexor communis which 

 supphes digit II. Syrinx tracheobronchial; carotid arteries both 

 present; liver with lobes subequal; gall bladder present; caeca non- 

 functional (rudimentary or absent) ; intestinal convolutions of type IV. 

 Oil gland present, usually feathered (nude in Cathartae) ; aftershaft 

 present (except in Cathartae and Pandionidae) ; powder-down patches 

 usually absent (present in Elanus, Circus, and Gypaetos) ; secondaries 

 aquincubital; rectrices 12-14. Young ptilopaedic and nidicolous. 



KEY TO THE SUBORDERS OF FALCONIFORMES 



a. Posterior, or ischioiliac, edge of os innoniinatum without any notch; external 

 nares imperforate; olfactory chaml^er small; maxillopalatines spongy; 

 precoracoid process large; metasternum 2-notched, or with 2 fenestrae, or 

 entire; hypotarsus without grooves; hallux incumbent, functional, connected 

 with flexor longus hallucis, the flexors of type III; no web or membrane 

 between second or third toes; lower larynx present, provided with one pair 

 of intrinsic (tracheobronchial) muscles; semitendinosus and accessory 

 semitendinosus muscles absent; oil-gland feathered; neck with large lateral 

 apteria, caeca present; myological formula A+ or BXY+; index digit of 

 manus without external claw, eggshells with green or reddish-yellow trans- 



lucence Falcones (p. 69) 



aa. Posterior or ischioiliac edge of os innominatum with a deep notch; external 

 nares perforate; olfactory chamber greatly developed; maxillopalatines 

 thin, scroll-like; precoracoid process rudimentary; metasternum 4-notched; 

 hypotarsus with two shallow grooves; hallux elevated, nonfunctional, con- 

 nected with the flexor perforans digitorum, the flexors of Type V; a distinct 

 web or membrane lietween basal phalanges of second and third toes; lower 

 larynx wanting; semitendinosus and accessory semitendinosus muscles 

 present; oil gland nude; neck without lateral apteria; caeca absent; myo- 

 logical formula AXY+ or XY+; index digit of manus with an external 

 claw; eggshells with yellow or greenish-yellow translucence. Cathartae (p. 3) 



Suborder Cathartae : American Vultures 



= Temnorhines Brandt, Jour, fiir Orn., 1853, 181. 



= Grypomorphae Carus, Handb. Zool., i, 1868-75, 305. 



>Necroharpages Sundevall, Fors. Fogelklassens, Meth. Nat. Av. Disp. Ten- 



tamen, 1872, 110 (includes Polyborinae). 



839094—50 2 



