WEST INDIAN MADREPORARIAN POLYPS. 



Bv J. E. DUERDEN. 



INTRODUCTION. 



The insufficiency of our knowledge of ttie morphology of the soft parts of the Madreporarian 

 corals has been conmiented upon by nearly all writers on the Anthozoa. Such a want at first 

 seems remarkable, when we consider for how long and how fully the hard parts have been known, 

 both to the zoologist and the paleontologist, and also the great abundance and wide distribution 

 of living corals. When, however, the geographical limitations of the greater number of recent 

 corals are taken into account, the difficulty of fully observing the polyps when alive, and more 

 especially of preserving them and of carrying out their anatomical study, the deficiency can be 

 in some measure understood. The investigations of a number of workers have already afforded 

 an insight into the general structure of Madreporarian polyps, especially of the simple forms; 

 but these are as yet insufficient to enable relationships of a broad systematic character to be 

 estal)lished. Practically all that has been achieved along such lines is the demonstration that 

 coral polyps are constructed on the same plan as the polyps of the principal group of the 

 Actiniaria, the Hexactinia?; in other M'ords, that the mesenteries and other organs are arranged 

 in a cyclical hexamerous manner. 



]\lany writers have contributed descriptions and figures of living coral polyps; yet so few 

 differences are determinable from external characters alone that Madreporarian morphology has 

 been but little advanced thereby. For admirable reproductions of the external characters of living- 

 corals the works of Quoy and Gaimard (1.S30), Dana (184(3), Klunzinger (1877), and the elab- 

 orate work of Saville Kent (1893), The Great Barrier Reef of Australia, should be consulted. In 

 a recent contrilnition Prof. H. de Lacaze-Duthiers (1897) has presented a very full account of 

 the corals met with in the Mediterranean, and the drawings of the living polyps are among the 

 finest we possess. Undoubtedly the best illustrations of West Indian shallow-water corals, mainlj' 

 limited, however, to the skeleton, are those accompanying the Report on the Florida Reefs, by 

 Louis Agassiz (188(i). In '"The Stony Corals of the Porto Rican Waters." Mr. Vaughan has 

 given thirty-eight photographic reproductions of the more familiar West Indian species (1901«), 

 followed shortly by a more complete series from Prof. A. E. Verrill (1901). 



Of the older writers on coral structure, Milne Edwards and Haiiue (18.57), in their classic 

 "Ristoire Naturelle des Coralliaires," have given all that was then possible with the limited means 

 of research available. It is only within the last two decades that any serious attempt has been 

 made to advance our knowledge of the anatomical structure of Madreporarian polyps. The late 

 Prof. H. N. Moseley, in 18S2, proved that Serlatojwra and PocJJlopum are true Madreporaria," 

 and in his "Challenger" Report on the Deep-Sea Madreporaria made many other additions to the 

 morphology of the group (1881). 



"Prof. A. E. Verrill (1869, p. 518), from descriptions and ilrawings of PociUnpora, had come to the same conclu- 

 sions as early as 1867. 



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