BIRDS OF NORTH AND MIDDLE AMERICA 5 



times closed to form fenestrae; keel of sternum very deep, extending 

 backward to extreme edge of sternum, the greatest curvature of its 

 free margin near its middle; spina externa and spina interna absent; 

 coracoid grooves shallow and broad, divided from one another in the 

 middle by a strong ridge; acrocoracoid without articular facets for 

 furcula; linea aspera for origin of subclavis extending backward to 

 within a short distance of the posterior end of the sternal plate; distal 

 extremities of furcula pierced by a pneumatic foramen; procoracoid 

 process rudimentary; index digit of manus with an external claw; 

 pelvis ciconiine, but iliac pockets present (absent in Ciconiidae) ; 

 postacetabular ilium shorter than ischium and the limitations of the 

 elements indicated posteriorly by a deep notch, the ischium being 

 continued backward in a sharp spine along the pubis, the latter pro- 

 jecting far beyond the ischium.^ Hypotarsus simple, with two shal- 

 low grooves; deep plantar tendons of type V; index digit of wing with 

 an external claw; basal phalanx of middle toe longer than either of 

 the succeeding ones; syrinx absent, the only muscles of trachea being 

 the sternotracheales, the intrinsic muscles entii'ely absent; semi- 

 tendinosus and accessory semitendinosus muscles present; expansor 

 secundariorum present; tendons of patagium ciconiine; tendons of 

 patagium ciconiine, the brevis consisting of a separate anterior and 

 posterior section, of which the latter is thinner and more diffuse, the 

 anterior tendon dividing into two, of which the foremost gives off a 

 slip to the longus; biceps slip absent; pectoralis primus muscle divided 

 into two parts; glutaeus I covers over biceps; glutaeus V present; 

 carotid arteries, both present; gall bladder present; caeca absent or 

 rudimentary; liver equilobed; crop present, well developed; tongue 

 large and fleshy, with denticulations along its upturned lateral 

 margins; stomach not a gizzard; secondaries aquintocubital ; rectrices 

 12-14; cervical pterylosis without apteria; oil gland nude; contour 

 feathers without aftershafts; head (sometimes neck also) naked in 

 adults, covered with short down in young; young ptilopaedic * pod 

 nidicolous, fed by regurgitation; eggs 1 or 2, deposited on bare earth, 

 or rock, or wood, usually in cavities; eggshells with yellow or greenish- 

 yellow translucence. 



The removal of the American vultures from very close association 

 with the true so-called birds of prey (suborder Falcones) has been 

 justified by the investigations of the best anatomists and systemists 

 for so long a time that it is scarcely worth while to refer to their former 

 inclusion within the latter group. It is sufficient to say that the 

 external resemblance between them and the Old World, or true, 



3 Pycraft, Proc. Zool. Soc. London, 1902, 318, 319. 



* Said by Sharpe (Review of Recent Attempts to Classify Birds, 1891, 78) to be 

 gymnopaedic in Sarcoramphus, but this is almost certainly an error. 



