60 THE SEA-SHORE 



leaps, with a mighty effort, right out of its old 

 coat! And as soon as it has done so the rent 

 closes up again, so that unless you look very 

 carefully indeed you cannot see it. You might 

 really think that two crabs were lying side by 

 side together. 



For about a couple of hours the crab now lies 

 perfectly still ; and if you were to feel it you 

 would find that its body was hard and knotted 

 all over. That is because its muscles are cramped 

 after the violent efforts which it has been making. 

 After a time, however, the cramp passes off. 

 Then the animal begins to grow. It grows 

 very fast indeed. In fact it grows so fast that 

 you can almost see it growing, and in less than 

 twenty -four hours it is sometimes nearly half 

 as big again as it was before. A new " shell " 

 then begins to form upon the skin, and in about 

 a couple of days more the animal is able to leave 

 its retreat, clothed once more in a suit of good 

 stout armour. 



That is the way in which crabs, and lobsters, 

 and shrimps, and prawns all grow. Once in 

 every year at least they get new " shells " ; and 

 every time that they do so they increase in size. 

 But after they reach a certain age they grow 

 no more; and the coats of mail which they are 

 wearing then are kept to the end of their lives. 



