84 THE WONDER OF LIFE 



to great depths. The Challenger explorers found that a 

 piece of wood sunk to the abysses was so heavy when 

 pulled up again that it sank in water. The muscles of a 

 dead animal, such as a whale, must undergo a tremendous 

 compression if the carcass sinks. 



FIG. 28. Deep-Sea Pycnogonid or " Sea Spider," Pipetta, with extra- 

 ordinary length of limb in proportion to the size of the body. The 

 males carry the eggs. (After Loman .) 



When a whale fills its lungs and ' sounds ', remaining 

 below the surface for ten minutes at a time (as the Prince of 

 Monaco proved), its body may be subjected to a consider- 

 able increase of pressure, which the ribs in particular have 

 to withstand. Mr. J. Y. Buchanan suggests that the 

 occurrence of a number of broken and repaired ribs on one 



