BIRDS. 37 



*** Toes 4 : two in front, two behind. 



Bill cered and liooked. . . . Psittaci, I. 



Bill lengthened, not cered. . . Picari^, H. 

 **** Toes 4: three in front, one behind. 



I. Toes not webbed at all, cleft to the base, or with the basal 



joints immovably coherent. 

 a. Hind toe inserted on a level with the rest and generally 

 longer than the shortest anterior toe. 

 h. Claw of hind toe at least as long as that of middle toe. 



f Bill without cere, never very strongly hooked ; outer 

 toe not versatile Passeres, G. 



ff Bill with cere, strongly hooked; outer toe usually 

 versatile; claws very sharp and strong. Raptores, J. 



hh. Claw of hind toe shorter than that of middle toe. 



X Bill stoutish; nostrils opening beneath a soft, swollen 

 membrane (shrunken in drying). Columb^, K. 



XX Bill tenuirostral, very slender; secondaries 6, very 



short. Humming-birds. . . Picari^e, H. 



aa: Hind toe elevated above the level of the rest, and usually 



shorter than the others. 



c. Bill tissirostral — culmen very short, but gape very wide 



and deep, reaching to below eyes. . Picari^, H. 



cc. Bill lengthened, not fissirostral. 



d. First primary emarginate, or else about as long as 



second. Limicol/e, M. 



del. First primary not emarginate, shorter than second. 



Alectorides, O. 



II. Toes syndactyle — without webbing, but with the outer and 



middle toes coherent half their length. . Picari^, H. 



III. Toes semipalmate ; two or three of them joined at base only 



by evident movable M^ebbing. 



e. Hind toe inserted on a level with the rest. 

 f. Tibia3 feathered below. 



g. Bill cered and hooked ; claws sharp and strong. 



Raptores, J. 



gg. Bill not cered and hooked ; nostrils opening beneath 



a soft, swollen membrane. . . Columr^, K. 



