220 
PELECANINiE. 
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 
father 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 ;f 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, 
