268 PHILOSOPHY OF ZOOLOGY. 



b. Feet with two toes. The outer one without a nail. 

 Phalanges, 4. 5. 



194. Strutuio. Ostrich. Bill depressed, soft at the 

 end. Large crop, with a smaller one between it and the 

 gizzard. Caecum long. Cloaca large. Struthio Camelus. 



PALMIPEDES. 



Toes webbed to the extremity. 



This great division contains birds which are truly aquatic. 

 The legs are short, and placed far behmd. In walking, 

 the body assumes nearly an erect position. Many of the 

 species dive readily, and, when under water, employ their 

 wings as cars to aid them in progressive motions. The 

 skin is thickly clothed with feathers, and a close covering 

 of down. The neck is usually longer than the legs, an ar- 

 rangement which is not observed to prevail in the other 

 groups. 



1. The hind toe united with tlie fore toes by a continuous 

 membrane. The outer toe is long, and the rest decrease 

 to the hind toe, which has a mesial direction. The open- 

 ings of the nostrils are indistinct, although the nasal 

 groove reaches nearly to the extremity of the bill. 



A. Base of the bill, and about the eyes, covered with a 

 naked skin. 



1. Margin of the bill sharp and entire, the extremity 

 hooked. 



Bill depressed. 



195. Onocuatulus. Pelican. Sides of the lower man- 

 dible slender, forming the margin of a large gular pouch. 

 Pelicanus Onocratalus. 



