200 



ARTHROPODS : CRUSTACEANS. 



Lobster or other Crustacean loses a leg or other organ, 

 another like it grows to supph- its place. But one of 

 the most remarkable facts about Lobsters and other 

 Crustaceans is, that from time to time they shed the 

 shell in one piece, so that the cast-off shell looks ex- 

 actly like the perfect animal, — antennse, eyes, jaws, 

 legs, paddles, and even every hair, are all just as they 

 were when they covered the live Lobster. The Lobster 



348. 



American Lobster. 



comes out of its shell through a rent on the back, and 

 is at first very soft ; it at once increases in size, and 

 in a few days its skin becomes as hard as the shell 

 which it cast off. This shedding of the shell is neces- 

 sary for the growth of this animal, for after the new 

 shell hardens further growth is impossible. When a 

 Lobster is ready to shed its shell, there are two hard, 

 stone-like bodies at the sides of the stomach, and it is 

 supposed that these furnish a part of the solid matter 



