156 METAZOAN PHYLA 



are not able to propel the ctenophores with a speed approaching that 

 attained by the coelenterate jellyfishes, the animals appear to have 

 more definiteness of movement. 



Like jellyfishes, ctenophores serve as food for many marine animals, 

 even for such large animals as whales. They are, however, of no direct 

 economic importance to man. 



