HYDEOIDS 197 



organized effort about it than the plan of feeding de- 

 scribed for quiet water. 



The food accumulated by the two methods mentioned 

 in the preceding paragraphs doubtless undergoes diges- 

 tion in the interior of the polyp and is here moved about 

 by the peristalsis of the proboscis already referred to. 



When the responses and activities of Corymorpha are 

 compared with those of an anthozoan polyp, their inef- 

 ficiency is most striking. This is especially well seen in 

 the tentacular responses to food. In an anthozoan the 

 tentacles when touched by a piece of food turn in many 

 directions till they have more or less entwined the food. 

 They become covered with a sticky mucus and they dis- 

 charge their nettling filaments with great freedom. 

 Finally by the action of their cilia and muscles the food 

 is delivered at the lips. In Corymorpha the proximal 

 tentacles are not provided with mucus and their one 

 muscular response is to wave toward the mouth, a re- 

 sponse that occurs as well when the food touches their 

 aboral faces, and is consequently left behind by their re- 

 sponse, as when it is on their oral face. No cilia are pres- 

 ent in Corymorpha to help transport the food to the 

 mouth. In Corymorpha the whole process of food gath- 

 ering has a strongly marked mechanical character that 

 makes it much less successful as a means of getting all 

 the food within reach than the operations carried out by 

 the anthozoan tentacle (Torrey, 1904 b). This lack of 

 close adjustment, which has been noticed in the tentacles 

 of Tubularia (Pearse, 1906) as well as in those of Cory- 

 morpha, runs through all the reactions of Corymorpha as 

 compared with those of the anthozoan polyps. 



Notwithstanding the general inefficiency of the re- 

 sponses of Corymorpha, this polyp contains among its 



