THE SCHOOL OF THE SHORE 51 



A common accident on the seashore is that 

 a crab gets its leg badly broken by a moving 

 stone. When that happens the crab goes in 

 for surgery. By a very forcible contraction of 

 the muscles at the base of the damaged leg 

 the crab manages to break it off across a weak 

 line. And just below this breaking line there 

 is inside the base of the leg a two-flapped 

 membrane which closes up the wound and 

 prevents bleeding. Inside the bandage a new 

 leg is formed in miniature, and at the next 

 moult this shoots out like a Jack-in-the-box, 

 and soon hardens. 



COLOUR CAMOUFLAGE 



The common shore-crab (Carcinus mcenas) 

 occurs in many colours when it is young, and 

 these sometimes harmonise exactly with the 

 rock of the pool in which the particular crab 

 lives. But there is no change of colour except 

 after a moult. It is different with the Aesop 

 Prawn {Hippolyte varians] which takes on the 

 colour of its surroundings, both when young 

 and when adult, and can change from one 

 colour to another with ease. It has a large 

 repertory red, yellow, blue, orange, olive, 



