FEEDING REACTIONS OF THE ROSE CORAL 

 (ISOPHYLLIA).i 



By F. W. Carpenter. 



Presented by E. L. Mark. Received July 5, 1910. 



Introduction. 



A NUMBER of investigators have studied in detail the structure of 

 the polyps of the Madreporaria, the group of corals which includes 

 the great majority of reef-building forms. Comparatively little atten- 

 tion has been paid, however, to the activities of the living zooids, 

 although the ultimate result of these activities, the formation of im- 

 mense quantities of limestone, is a remarkable biological phenomenon, 

 and one of very considerable geological importance. 



The present paper is intended as a contribution to the field of coral 

 physiology, and is concerned mainly with the reactions which follow 

 the stimulation of the polyp by means of nutrient substances. Since 

 the corals belong to the pliylum of the Coelenterata, in which we have 

 learned to look for the first appearance of a differentiated mechanism 

 for neuro-muscular reflexes, the facts here recorded have at least an 

 incidental bearing on the question of the phylogenetic origin of the 

 nervous system. 



The work on which the paper is based was done at the Bermuda 

 Biological Station for Research in the summer of 1909. During a 

 period of several weeks, observations were made on the feeding behav- 

 ior of rose-coral polyps belonging to the genus Isophyllia. Of this 

 genus three species are recorded by Verrill (: 02) for the Bermuda Is- 

 lands, viz., dlpsacea, frag ills, and multijiora, the first two being much 

 more common than the last. Since the specific characters lie in the 

 skeleton, it is not possible to determine with certainty the species of 

 a living colony, but it is known from the subsequent examination of 

 several skeletons that dlpsacea occurred in the material used, and in 

 all ^xo\>ah\\\ty frag His was also represented. The question of species 



^ Contributions from the Bermuda Biological Station for Research, No. 20; 

 also Contributions from the Zoological Laboratory, University of Illinois, 

 under the direction of Henry B. Ward, No. 4. 



