STARFISH, SEA-URCHINS, AND SEA-CUCUMBERS. 47 



and if exposed would be easily rolled out of place. They 

 are eaten in great numbers by cod and other large fish, 



FIG. 48. Echinus half way over. 



which gulp them down whole, their prickly shell seeming 

 to make little difference to their captors. 



FIG. 49. Echinus nearly righted. 



The Sea-cucumbers While the lowest Echinodefms are 

 the stalked starfish or crinoids (Figs. 39 and 50), the highest 



