xxviii NORTH AMERICAN BIRDS. 



Analysis of Families of STEGANOPODES. 



Bill rather longer than head, cleft to eyes, very stout at base, tapering to the 

 decurved, but not hooked, tip. Nostrils abortive. Gular sac moderate, naked. 

 Wings rather long, pointed. Tail long, stiff, cuneate, twelve to fourteen feathered. 

 Feet nearly beneath centre of equilibrium. General configuration goose-like . Sulidce. 



Bill several times longer than head, .^lender but strong, depressed, perfectly 

 straight, with small distinct hooked nail at end. Nostrils very small. Gular sac 

 enormous. Mandibular rami meeting only at tip. Wings extremely long, with 

 upward of forty remiges. Tail short, rounded, of twenty or more feathers. 

 Legs beneath centre of equilibrium, extremely short and stout . . . Pelican id(c. 



Bill about as long as head, stout, straight, scarcely tapering, strongly hooked. 

 Nostrils abortive. Gular sac moderate, but evident; mostly naked. Wings 

 short. Tail large, fan-shaped, scansorial, of twelve to fourteen broad stiff feath- 

 ers, exposed to the base. Legs inserted far behind centre of equilibrium . Graculidce. 



Bill rather longer than head, slender, perfectly straight, tapering to an acute 

 tip. Gular sac small. Nostrils minute. Wings and tail, and general configura- 

 tion, as in the last Plotidic. 



Bill much longer than head, straight, stout, strongly hooked. Nostrils very small. 

 Gular sac well developed. Wings exceedingly long, strong, and pointed. Tail 

 exceedingly long, deeply forked. Feet extraordinarily short ; tarsi partly feath- 

 ered Tachypetidce. 



Bill about as long as head, straight, stuut, tapering to an acute tip. Nostrils 

 small. Gular sac rudimentary, feathered. Wings moderate, pointed. Tail 

 short, but with two central feathers extraordinarily prolonged and filamentous. 

 Feet small, beneath centre of equilibrium Phcethontidce. 



Analysis of Families of LONGIPENNES. 



Nostrils not tubular, lateral, perforate. Bill witli continuous covering, or only 

 broken by a sort of cere, hooked or straight to the end. Hallux small and ele- 

 vated, but always present ........... Laridce. 



Nostrils tubular, disjoined and lateral, or oftenest superior and united in one 

 double-barrelled tube. Covering of bill in several pieces ; bill always hooked. 

 Hallux minute, rudimentary, or absent ....... ProceUrt.riidce. 



Analysis of Families of PYGOPODES. 



Feet four-toed, palmate. Hallux lobate, connected at base with base of inner 

 toe. Tail perfect. Head closely and completely feathered. Nostrils with a de- 

 pending lobe or flap. Bill straight, compressed, acute .... Colymhidce. 



Feet four-toed, lobate. Hallux lobate, free. Tail rudimentary. Head with a 

 naked loral strip and bristly or variously lengthened feathers. Nostrils simple. 

 Bill straight or decurved at end, compressed, acute ..... Podidpidce. 



Feet three-toed, palmate. Hallux absent. Tail perfect. Head closely feathered 

 or variously crested. Nostrils simple. Bill of indeterminate shape . . . Alcida. 



