PREHENSION OF LIQUID FOOD. 117 



sucking apparatus, that a lamprey has been 

 raised out of the water with a stone, weighing 

 ten or twelve pounds, adhering to its mouth. 



Humming birds have a long and slender 

 tongue, which can assume the tubular form, like 

 that of the butterfly or the bee, and for a similar 

 purpose, namely, sucking the juices of flowers. 

 Among the mammalia, the Vampire Bat affords 

 another instance of suction by means of the 

 tongue, which is folded into a tubular shape 

 for that purpose. But suction among the mam- 

 malia is generally performed by the muscles of 

 the lips and cheeks, aided by the movements 

 of the tongue, which, when withdrawn to the 

 back of the cavity, acts like the piston of a 

 pump. In the Lamprey, this hydraulic action 

 of the tongue is particularly remarkable. Many 

 quadrupeds, however, drink by repeatedly dip- 

 ping their tongue into the fluid, and quickly 

 drawing it into the mouth. 



§ 2. Prehension of Solid Food. 



When the food consists of solid substances, 

 organs must be provided ; first, for their pre- 

 hension and introduction into the mouth ; se- 

 condly, for their detention when so introduced ; 

 and thirdly, for their mechanical division into 

 smaller fragments. 



