ADAPTATIONS OF STRUCTUKE. 277 



power of darting or shooting with great rapidity 

 through the water. This act is performed by 

 means of the tail, the broad plates at the end of 

 which put in motion by the powerful muscle con- 

 necting them with the anterior part of the body, 

 strike the water with immense force, enabling the 

 lobster to project itself many feet. One of the 

 most singular feats performed by the creature is 

 that of throwing itself, apparently with one stroke 

 of its tail, directly into its hole, from a distance, 

 it is said, of twenty or thirty feet. 



In all the Crustacea, crabs as well as lobsters, 

 the shelly armour which they wear being inelastic 

 and incapable of accommodating itself to the in- 

 creased size of the animal, an admirable provision 

 is made by which, from time to time, the covering 

 can be thrown off, and its place supplied by a new 

 suit perfectly adapted to the convenience of the 

 possessor. But for this provision the animal upon 

 increasing in size must inevitably perish. 



Crabs and lobsters are said to cast their shells 

 once a year, and the facility with which this ap- 

 parently impossible process is performed is truly 

 marvellous. At first sight it would appear as im- 

 possible for the animal to extricate itself from its 

 unyielding envelope as it would have been for a 

 soldier, in the days when complete suits of armour 

 were worn, to find his way out of his steel clothing 

 without opening the joints and separating the 

 pieces composing it. Impossible as the process 

 appears, however, the crab and lobster are gifted 

 by the express design of the All-wise Creator 



T 3 



