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jth March, 1882. 



The President, R. L. Patterson, Esq., in the Chair. 



A Paper was read by Professor Cunningham, M.D., F.L.S., on 

 CORALS AND CORAL ISLANDS. 



ABSTRACT. 



After a reference to some popular misconceptions with respect 

 to the nature alike of corals and coral-forming animals, and a 

 short notice of certain calcareous bodies, animal and vegetable, 

 liable to be confounded by the uninstructed with these forma- 

 tions, it was stated that all true corals were the internal secre- 

 tions of animals included in the sub-kingdom Ccelenterata, the 

 great majority being the skeletons of Actinozoa, while a cer- 

 tain number, as revealed by recent researches, are those of Hy- 

 drozoa. 



The Actinozoan corals were first treated of, the typical 

 structure of an Actinozoon, as illustrated by a common Actinia 

 or Sea-Anemone, being described ; and it was shown that, in 

 accordance with the number of tentacles and of the vertical 

 radiating partitions (or mesenteries) of the body-cavity, the 

 members of the class might be included in one or other of 

 two groups — i.e., those possessed of numerous tentacles and 

 mesenteries (Polyactinia or Zoantharid), and those with only 

 eight tentacles and eight mesenteric folds (Octactinia, or 

 Alcyonarid). 



Of the coralligenous Polyactinia, some resemble the Sea- 

 Anemone in being solitary animals, each living being having a 



