210 FUNCTIONS AND INSTINCTS. 



the centre close the mouth. 1 Altogether this 

 complex machine consists of twenty-five pieces 

 moved by thirty-five muscles. The disposition 

 of these pieces, Lamarck observes, and of their 

 moving muscles, indicate that the parts of this 

 machine can have only a common movement, 

 and no one of them an individual or separate 

 one ; but it appears from Cuvier's elaborate de- 

 scription of this wonderful and complex machi- 

 nery, if I understand him right, that the action of 

 certain muscles will give to any one of the teeth 

 that form the pyramids an independent motion. 

 This powerful apparatus, which the animal can 

 incline in different directions, indicates a kind of 

 food, less easy to bruise and masticate than what 

 we have seen satisfies the whale, and these or- 

 gans afford a singular contrast to those by which 

 that enormous monster masticates its food. 



The Echinidans, whose station appears to 

 be often near the shore upon submerged ledges 

 of rock, feed upon whatever animal they can 

 seize. We have seen that they sometimes 

 turn upon their back and sides, as well as 

 move horizontally, this enables them more 

 readily to secure their food, with the aid of 

 the numerous suckers in the vicinity of their 

 mouth, which when once they are fixed, never 

 let go their hold till the animal is brought 

 within the action of their powerful jaws. La- 



1 PLATE III. FIG. 9. 



