AND PHYSIOLOGY. 



411 



tute generally of papillae. In some of this class it is hardly 

 perceptible, while in Serpents, Toads and the Chameleon, it 

 is very long and capable of rapid motion. In Chameleons and 

 Serpents, when the tongue is at rest, it lies in a kind of sheath 

 at the base of the mouth. That of the latter is forked at its 

 apex, while the former has a concave disk at its point covered 

 by a viscid secretion, which, by the dexterity of the animal, 

 can be thrown at once against the insects flying in the air, 

 thus securing its food. In this case also the tongue seems 

 longer than the body itself. 



Fig. 3U. 



Tongue of Common Fly. a, Lobes of Lingula. 5, Portion enclosing the Lancets 

 formed by the Metamorphosis of the Maxilla, c, Maxillary Palpi, a, Portion of 

 one of the Metamorphosed Trachece enlarged. 



How does the chameleon obtain his insect food ? 760. Have fishes any tongue, or the 

 sense of taste? 761. How- well is this organ developed in some of the lower animals? 

 762. Describe the shape of the nose. Of what is it principally composed ? 



