JAWS OF THE ECHINUS. 119 



and in them we find a remarkable perfection in 

 the organs of mastication. The mouth of the 

 Echinus is surrounded by a frame-work of shell, 

 consisting of five converging pieces, each armed 

 with a long tooth ; and for the movement of 

 each part there are provided separate muscles, 

 of which the anatomy has been minutely de- 

 scribed by Cuvier. In the shells of the echini 

 that are cast on the shore, this calcareous frame 

 is usually found entire in the inside of the outer 

 case ; and Aristotle having noticed its resem- 

 blance to a lantern, it has often gone by the 

 whimsical name of the lantern of Aristotle. 



In all articulated animals which subsist on 

 solid aliment, the apparatus for the prehension 

 and mastication of the food, situated in the 

 mouth, is exceedingly complicated, and admits 

 of great diversity in the different tribes ; and, 

 indeed, the number and variety of the parts of 

 which it consists is so great, as hardly to admit 

 of being comprehended in any general descrip- 

 tion. In most insects, also, their minuteness is 

 an additional obstacle to the accurate obser- 

 vation of their anatomy, and of the mechanism 

 of their action. The researches, however, of 

 Savigny* and other modern entomologists have 

 gone far to prove, that amidst the infinite vari- 



* See his " Theorie des Ore;anes de la bouche des Animaux 

 invert^bres et articules," which forms the first part of the '^Vle- 

 moires siir les Animaux sans vertebres." Paris, 1816. 



