BOOK <W NATURE LAID OPEN. 137 



little cables employed in mooring a muscle; each 

 cable is scarcely two inches long, but they are all 

 spun by herself, and the tongue is the instrument 

 which not only produces these numerous threads, but 

 serves also instead of arms and legs on other occa- 

 sions The Limpet, when she has occasion to un- 

 moor, finds means to disengage herself without any 

 great effort, and to move from her place by the same 

 muscle by which she adhered so firmly to her an- 

 chorage. Even Oysters are said not to be destitute of 

 the power and the instinctive sagacity to turn them- 

 selves round when thrown irregularly into a vessel 

 of water, so that the concave shells may remain 



downmost, in order to retain their favourite liquor. 



I 



Uses of Shell-fish. 



From the number of animals which prey upon in- 

 sects, it was inferred, that the principal object the 

 Creator had in view in the formation of these, was 

 the subsistence of many of the larger orders of crea- 

 tures ; so, from the numerous herds of shell-fish, 

 which, in a great degree, resemble insects, and eve- 

 ry where abound among the beds of the ocean, and 

 the extraordinary digestive faculties of the finny 

 tribes, we have reason to conclude, that the former 

 were principally intended and brought into existence 

 for food to the lifter- We will, however, mention a 

 few particulars in which the crustaceous tribes may 

 also be said to be otherwise serviceable. 



