636 ME. J. E. DTJEEDEN ON THE RELATIONS OF 



majority, if not all, o£ the Hexacorallia are closely related to 

 the Hesactiniae." 



The knowledge to hand of the morphology of the soft parts 

 in both Actiniaria and Madreporaria has, as yet, been insufficient 

 to enable a closer relation to be demonstrated. To establish 

 such requires an extended acquaintance with the outward form, 

 anatomy, and histology of a large number of representatives of 

 both groups. Such characters are now known for an abundant 

 and rapidly increasing series of Actiniae, but the corresponding 

 details for the coral polyps are not so large. 



"While investigating the numerous Stichodactylince occurring 

 in the West Indian area, certain features were presented by 

 three distinct genera — Rhodactis, JRicordea, and Corynactis ; 

 features which distinguished them from practically all other 

 Actiniaria, and which conformed with characteristics known to 

 occur in coral polyps. Instituting a comparison of upwards of 

 the thirty' species of anemones met with in Jamaican waters and 

 of as many coral polyps as could be procured, with what is already 

 known from the researches of Koch, Heider, Bourne, Powler, 

 and others, the result has been a complete demonstration to 

 my mind that no morphological character appears in the Madre- 

 poraria which does not also occur in the Actiniaria, and that we 

 possess in the above genera of Seccactinice, and possibly in 

 others, forms which differ in no respect from the polyps of corals, 

 except, of course, such as concern the production of the calca- 

 reous skeleton. While in the present state of our knowledge it 

 cannot be asserted that they belong to actual coral families, the 

 combinations of the details disclosed appear to warrant the 

 assertion that their relationship with the coral polyps is closer 

 than with the anemones. 



The present communication is but preliminary and suggestive 

 in character. It is hoped that when further study has been 

 conducted on the form and anatomy of the soft parts of corals, 

 a fuller contribution may be possible. 



Systematic. 

 The genus Rliodactis is restricted by Milne-Edwards (1857, 

 p. 293) to an anemone, U. rhodostoma, met with in the Eed 

 Sea, and distinguished by the possession of simple tentacles 

 around the margin of the disc and mouth, with other branching 

 tentacles occupying most of the area between. Duchassaing 



