220 PELECANINuE. 





would not appear to the student to have any very direct 

 affinity, but which he would recognise as parts of a sys- 

 tem, were he to examine the internal structure, and es- 

 pecially the digestive organs of the Anhingas, Pelicans, 

 Frigate-birds, Boobies, and Phaetons. Some of the ge- 

 neral characters of the family are as follows. 



Body elongated, rather slender ; neck long, or mode- 

 rate, generally thick ; head ovate. Bill longer than the 

 head, opening to beneath or beyond the eyes, generally 

 rather slender, straight ; upper mandible with the ridge 

 separated from the sides by grooves, and terminated by 

 a narrow, generally decurved, pointed unguis; lower man- 

 dible with the crura elastic and extensile, the angle very 

 long and narrow, the tip unguiculate. Skin of the throat 

 more or less extended and bare, so as to form a pouch ; 

 space around and before the eye generally bare. Eyes 

 rather small, nostrils basal, lateral, linear ; small, or en- 

 tirely obliterated. Apertures of ears very small. Tongue 

 extremely diminutive, triangular, fleshy; oesophagus ex- 

 cessively wide, more dilated below; proventricular glands 

 in two discontinuous patches; stomach very small, slight- 

 ly muscular, with the epithelium smooth; a globular lobe 

 at the pylorus in every species ; intestine long and slen- 

 der ; coeca small, cylindrical ; cloaca large and globular. 

 Trachea without inferior laryngeal muscles. Feet short, 

 stout ; tibia bare at its lower part ; tarsus compressed ; 

 toes four, all connected by membranes, the inner toe 

 small, and directed inwards and backwards, the outer 

 longest ; claws short, strong, curved, that of the third toe 

 generally pectinate. Plumage soft, blended, on the back 

 compact and imbricated ; wings long ; tail of moderate 

 length, narrow, rounded, the shafts of its feathers strong. 



These birds present a great uniformity in the struc- 

 ture of the digestive organs and feet, as well as in the 

 form of the skeleton ; but they differ greatly in external 

 appearance, and in habits; some swimming on the surface, 



