1892.] 



Note on the Structure of Rhabdopleura. 



133 



The epistome corresponds to the proboscis of Palanoglossus and 

 Cephalodiscus, and, like them, contains a portion of the coelom, the 

 anterior or prae-oral body cavity, completely shut off from the other 

 portions of the ccelom. 



The collar region (thorax of Lankester) contains the central section 



