BIRDS OF NORTH AND MIDDLE AMERICA 



Gruiformes with the metastemum entire; supraorbital furrows 

 present, well developed; occipital foramina present (except in Pso- 

 phiidae) and furcula Y-shaped. 



Palate schizognathous ; nares schizorhinal (holorhinal in P'so- 

 phiidae), pei'vious; basipterygoid processes absent; occipital 

 fontanelles and supraorbital glands present; interorbital septum 

 incomplete; cervical vertebrae 17-20; fused dorsal vertebrae 2-3 (4) ; 

 complete ribs 6-7; metasternum entire; spina externa sterni present 

 (except in Psophiidae), "enormous," spina interna absent; hypo- 

 tarsus complex; thigh-muscle formula ABXY+ (usually), BXY+, 

 XY+ ; the ambiens, semitendinosus and accessory semitendinosus 

 muscles present; biceps slip present; expansor secundariorum pres- 

 ent ; anconaeus with a broad humeral slip ; deep plantar tendons of 

 type I, united by a strong vinculum ; stomach a strong gizzard, the 

 proventriculus zonary; gall bladder present; caeca (1 or 2) large; 

 intestinal convolutions of type I (as in Ralli and Otides) ; syrinx 

 tracheobronchial ; hallux present ; oil gland nude or tufted ; af tershaft 

 present; powder downs absent; adult downs on both pterylae and 

 apteria; cervical pterylosis with lateral apteria; fifth remex absent 

 (aquincubital) or present (quincubital) ; rectrices 10-12. 



KEY TO THE FAMILIES OF GRUES 



a. Nares holorhinal ; occipital foramina absent ; hypapophyses on 3 dorsal verte- 

 brae; spina externa sterni absent; wing eutaxic (quintocubital) ; rectrices 



10; bill short, almost galline Psophiidae (extralimital)* 



CO. Nares schizorhinal; occipital foramina present; hypapophyses on cervical 



vertebrae only; spina externa sterni present; wing diastataxic (aquinto- 



cubital) ; rectrices 12; bill elongated, nongalline. 



6. Femorocaudal muscle absent; caeca situated laterally and close together 



(peculiar) ; hallux large, nearly as long as basal phalanx of middle 



toe, incumbent ; middle toe at least two-thirds as long as tarsus ; head 



completely feathered; bill not shorter than tarsus Aramidae (p. 27) 



6&. Femorocaudal muscle present (except in genus Balearica) ; caeca situated 

 opposite one another; hallux small, much shorter than basal phalanx 

 of middle toe, elevated; middle toe less than half as long as tarsus; 

 head partly naked (except in young) or else with ornamental plumes; 

 bill much shorter than tarsus Gruidae (p. 6) 



" =Hilebat8e Vieillot, Analyse, 1816, 60.=Psophid«e Lilljeborg, Proc. Zool. Soc. 

 London, 1866, 15. = Psophiidae Bonaparte, Consp. Gen. Av., ii, 1857, 102. — Carus, 

 Handb. Zool., i, 1868-75, 341.— Fiirbringer, Unters. Morph. Syst. Vog., ii, 1888, 

 1208, 1566.— Peters, Check-list Birds of World, ii, 1934, 155.=Psophiidje Sclater 

 and Salvin, Norn. Av. Neotr., 1873, viii, 141.— Stejneger, Stand. Nat. Hist., iv, 1885, 

 122, in text.— Sharpe, Cat. Birds Brit. Mus. xxiii, 1894, xii, 278; Hand-list, i, 1899, 

 xvii, 181. — Beddard, Struct, and Classif. Birds, 1898, 374.=Psophiin8e Bonaparte, 

 Consp. Gen. Av., ii, 1857, 102.— Psophiinse Knowlton, Birds of World, 1909, 337.= 

 Psophinse Lilljeborg, Proc. Zool. Soc. London, 1866, 17.=Psophi{e (suborder) 

 Sharpe, Rev. Rec. Att. Classif. Birds, 1891, 74 ; Hand-list, i, 1899, xvii, 181. (Com- 

 posed of a single genus, Psophia Linnaeus, containing about half a dozen species, 

 peculiar to the Amazon region and the Guianas in South America.) 



