THE CLASS BIRDS. 



291 



wading, have the limbs (pattes) slender, of great length, and 

 naked, or without feathers as far as the knee (Fig. 233) ; hence 

 their name of echassiers, or waders. Finally, in some species 

 the feet (pattes, digital part of the foot) are palmated, and 



Fig. 232. African Ostrich. 



Fig. 233. Echasse d'Europe. 



thus converted, by an expansion of the integuments, into a 

 kind of oar. The laxity of this membrane permits of the 

 full expansion of the foot, as may be seen in ducks (Fig. 234), 

 swans, and in a great number of aquatic birds. 



434. The tactile sensibility is but little developed in 

 birds, and the form of their wings and feet is also unfavour- 

 able for its exercise. The taste is more or less obtuse, and 

 their cartilaginous tongue, without nervous papillae, seems 

 ill-adapted for taste (Fig. 247). They seem to swallow their 

 food without tasting it. The sense of smell appears stronger, 

 but yet not much developed. The nasal fossae are hollowed 

 out of the base of the upper mandible (Fig. 223), without 

 communicating with the sinuses. They have a very vascular 

 pituitary membrane, and three cartilaginous laminae (cornets) 

 rolled on themselves, resembling the turbinated bones of 

 u2 



