—_— oe 
' like a gannet, and makes 
PELECANID®, PELICANS. 299 
only at their apex; the long broad interramal space, and the throat, occupied by an 
enormous membranous sac. Nostrils abortive. Wings extremely long, in the 
upper and fore-arm portions, as well as the pinion, with very numerous remiges. 
Tail very short, of 20 or more feathers. Feet short, very stout. Size large. 
The remarkable pneumaticity of the body (shared however by the gannets) has 
been already described. A principal osteological character is, that ‘‘the inferior 
edge of the ossified interorbital septum rises rapidly forward, so as to leave a space 
at the base of the skull, which is filled by a triangular crest formed by the union of 
the greatly developed ascending processes of the palatines” (Hualey). The tongue 
is a mere rudiment. But the most obvious peculiarity of these birds is the immense 
skinny bag hung to the bill, capable of holding several quarts when distended ; its 
structure is as follows: The covering is ordinary skin, but very thin; the lining is 
skin modified somewhat like mucous membrane ; between these ‘‘ is interposed an 
equally thin layer, composed of two sets of very slender muscular fibres, separated 
from each other, and running in opposite directions. The outer fibres run in 
fascicles from the lower and inner edge of the mandible, those from its base passing 
downward, those arising more anteriorly passing gradually more forward, and reach 
the middle line of the pouch. The inner fibres have the same origin, and pass in a 
contrary direction, backwards and downwards. From the hyoid bone to the 
junction of the two crura of the mandible, there extends a thin band of longitudinal 
muscular fibres, in the centre of which is a cord of elastic tissue. By means of 
this apparatus, the sac is contracted, so as to occupy but little space. When the 
bill is opened, the crura of the lower mandible separate from each other to a 
considerable extent [in their continuity —not at the symphysis], by the action of 
muscles inserted into their base, and the sac is expanded” (Audubon). This organ 
is used like a dip-net, to catch fish with ; when it is filled, the bird closes and throws 
up the bill, contracts the 
pouch, letting the water 
run out of the corners of 
its mouth, and swallows 
the prey. Pelicans feed 
in two ways; most of 
them, like our white one, 
scoop up fish as they 
swim along on the water ; 
but the brown species 
plunges headlong into ~ 
the water from on wing, Z 
Fic. 197. Bill and gular pouch of White Pelican. 
a grab, often remaining submerged for a few seconds. Neither species often catches 
large fish ; they prefer small fry of which several hundred may be required for a full 
meal. The prevalent impression that the pouch serves to convey live fish, swimming 
in water, to the little pelicans in the nest, is untrue; the young are fed with par- 
tially macerated fish disgorged by the parents from the crop. As Audubon remarks, 
it is doubtful whether a pelican could fly at all with its burden so out of trim. 
The gular pouch varies in size with the different species, reaching its greatest 
development in the brown pelican, where it extends half-way down the neck in front, 
is a foot deep when distended, and will hold a gallon. Besides this singular 
adjunct, the bill of our white pelican has another curious structure, not found in 
other species. The culmen is surmounted near the middle by a high thin upright 
