CTENOPHORA. 313 



name Ctenophora. They receive this name (meaning comb- 

 bearers) from the fact that the usually globular body has 

 eight rows of vibratile organs, each row being composed of 

 series of hairs arranged much like the teeth of a comb. 

 They have an alimentary canal, which branches so that a 

 portion underlies each row of combs. They, however, differ 

 from all true Coelenterates in the absence of nettle-cells, and 

 in a number of other features which need not be described 

 here. All of the Ctenophores are marine. 



