602 Scientific Proceedings^ Royal Dublin Society. 



change I have just referred to has taken place. Whether I am 

 correct in my opinion on this matter or not there can be no doubt 

 tliat this collection of Professor Haddon's emphasizes most stronglj'- 

 the fact that the colour of Distichopora can no longer be regarded 

 as tlie principal character for the separation of the species. It is 

 quite possible that both D. coccinea and D. rosea should be con- 

 sidered to be distinct species, but until we have some further 

 information concerning the anatomy of the soft parts these species 

 must be considered to be quite provisional. 



The first notice we have of this Hydrocoralline is in the 

 Rariteitkamer of Rumphius, vol. vi., p. 243, where it is described 

 under the name of LitJiodendrum saccharaceum riibrum. 



In Pallas' " Elenchus Zoophytorum," p. 258, there is a 

 description of a Distichopora under the name Millepora violacea. 

 Ellis adopted the name Millepora violacea, and recognized some of 

 the principal characters of the genus referring to the two kinds of 

 pores on the edge of the branches, and to the prominences on the 

 surfaces which he supposed to be the " ovaries." There are two 

 very good figures on Plate 26, which are undoubtedly represen- 

 tations of Distichopora, but, unfortunately, the description of this 

 plate was not found among Ellis's papers, and there is no refe- 

 rence to it in the text. Lamarck was the first to introduce the 

 generic name Distichopora. He adopted Pallas' specific name, and 

 the species became Distichopora violacea. 



I have given this brief summary of the early history of our 

 knowledge of the genus to justify the step I am taking in naming 

 the specimens before me Distichopora violacea. If it be eventually 

 proved that there are not sufiicient reasons for separating into 

 separate species the red, pink, yellow, and white varieties that 

 have been described, Distichopora violacea is the specific name that 

 must remain. 



There is no need to give an account of the coenosteum of 

 Distichopora, for Moseley's description, p. 95, is very complete and 

 accurate. The only point in which his description does not quite 

 agree with the specimens before me lies in the fact that the occur- 

 rence of pores on the flabellar surfaces are not of such rare occur- 

 rence as he seems to have considered them to be. The figures on 

 PI. xviii. show that in all the specimens there are several rows of 

 pores on the flabellar surfaces. In a small specimen of a violet 



