THE CRAB. 337 



Description. 



conduct indicates more sagacity than could be 

 expected from an animal of this low order. 



CRABS. 



CRABS have in general eight legs, (some, 

 however, have six or ten,) besides two large 

 claws, which serve the purposes of hands. They 

 have two eyes, situated on tubercles projecting 

 from the head, and movable in any direction. 

 When the extremities of these are viewed with a 

 glass, they are found to be composed of a multi- 

 tude of lenses, like the eyes of insects. For a 

 sense of touch they are furnished with antennae, 

 and palpi, or feelers. They have likewise a heart, 

 with arterial and veinous vessels, and branchiae, 

 or gills for respiration. Their jaws are trans- 

 verse, strong, and numerous ; and the stomach 

 is furnished with internal teeth. 



These animals regularly cast their shell once a 

 year. This is a process that occupies some time, 

 and seems to be attended with much pain. Du- 

 ring the operation, and for a little while after- 

 ward, their skins are soft, in consequence of 

 which multitudes of them are devoured by aqua- 

 tic animals, now stronger than themselves. At 

 this time those calcareous concretions, vulgarly 

 called crab's eyes, are found in their stomachs. 

 When any of thg claws are broken off they are 

 reproduced. 



VOL. v. NO. 21. 2 u 



