PELECANIDiE, PELICANS. 



299 



onlj^ 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 bj^ a triangular crest formed by the union of 

 the greatly developed ascending processes of the palatines" {Huxley). The tongue 

 is a mere rudiment. But the most obvious peculiarity of these birds is the immense 

 skinn}' 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 oppjosite 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" {Audiibon). This organ 

 is used lilie 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, 

 like a gannet, and makes 

 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 j'oung 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 difl'erent 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 iDclican has another curious structure, not found in 

 other species. The culmen is surmounted near the middle by a high thin upright 



Fig. 197. Bill and gular pouch of White Pelican. 



