TONGUES 95 



front is free if it be free anywhere, and two points 

 may project backward from the rear edge, as may be 

 seen in the tongues of birds. These points are aids 

 in swallowing. In one genus of Hzards {Chaleis) 

 these forks are especially long. 



In the tortoise-forms, the tongue is usually short, 

 flat, and cupped, rather fleshy and smooth, as if it 

 were a tasting organ. It is much like that of some 

 fishes, and, within small limits, very movable, though 

 it can not be thrust out. In the crocodilians it is 

 fast to the lower jaw all around and acts merely as a 

 floor to the mouth. 



In the lizards it takes on two extreme forms gen- 

 erally, with many shapes between these. In most it 

 is flat and much the same thickness everywhere 

 (forked behind or (not), and is usually notched in 

 front. This kind of tongue rarely runs in any sheath 

 throughout. One type of this form is flattish and 

 runs in a sheath at the base only ; and another sort 

 is thick at the base, thin and wide at the tip, which 

 latter runs under a sheath or strap. 



The other form of tongue is long, slim, and deeply 

 forked at the tip. Sometimes it consists of only two 

 mere threads. This is the kind found in all snakes 

 and two or more large families of lizards. In the 

 snakes and many lizards (monitors, etc.) this slim 

 tongue is entirely sheathed when inside the mouth, 

 and is thrust forth very rapidly either for feeling or 

 threatening ; but the tongue itself is perfectly harm- 

 less — even for securing prey. 



In other lizards this slim, forked tongue is cov- 



