﻿RECENT RESULTS ON THE MORPHOLOGY AM) 

 DEVELOPMENT OF CORAL POLYPS 1 



By J. E. DUERDEN 

 INTRODUCTION 



Students of the coelenterates have long been aware of the insuffi- 

 ciency of our knowledge of the morphology and development of the 

 animals which produce the calcareous skeletons popularly known as 

 corals. The skeletons themselves are thoroughly known, even to 

 their microscopic detail, but of the polyps which formed them, and 

 which covered them while alive, we know comparatively little. 



It is not difficult to assign a reason for this. It has been the 

 privilege of few naturalists to make a prolonged stay within tropical 

 regions, which are the home of by far the greater number of living 

 corals, especially of the larger massive forms which make up coral 

 reefs ; yet it is only by direct study on the spot that many of their 

 characteristics can be determined, their development followed, or 

 suitable material procured for later anatomical and histological in- 

 vestigation. Beyond the observation of their living external charac- 

 ters, the polyps must be narcotized and preserved under proper 

 conditions, and slow decalcification carried out to remove the hard 

 calcareous skeleton so as to obtain the soft tissues in their natural 

 relationships for microscopic examination. 



A residence for the last few years within the West Indies, in the 

 region of coral reefs, has afforded me the opportunity of investi- 

 gating the morphology and development of a certain number of 

 coral polyps. In all about thirty species have been fully examined, 

 both in their living condition and anatomically, and the development 

 of several forms has been followed for longer or shorter periods. 

 Only the principal results can be here outlined. 2 



1 A lecture delivered at the Marine Biological Laboratory, Woods Hole, 

 Massachusetts. 



2 Fuller details will be found in volume vil, 7th memoir, of the Memoirs of 

 the National Academy of Sciences, and in a series of four shorter papers 

 in the Annals and Magazine of Natural History from May, 190^, to February, 

 1903. 



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