8 Proceedings of the Royal Irish A cadeniy. 



these two genera have never been investigated ; and I have been unable to 

 obtain an authentic specimen of either of these, so that, for the present, they 

 must remain as problematical genera. 



It is exti'emely doubtful whether Verrucella and Gorgonella can be 

 regarded as distinct ; but, in the present memoir, it is not proposed to deal 

 with the various species which have, from time to time, been referred to 

 them. At the same time it must be noted that a very fruitful study might 

 be made with regard to these forms. 



Excluding, then, Phenilia, Heliania, Gorgonella, and Verrucella, it might 

 be of advantage, before proceeding to examine and differentiate the various 

 genera and species, to trace briefly the different bases of classification which 

 have from time to time been adopted in regard to the six genera under 

 consideration. 



The oldest of the genera under consideration is Scirpearia, which was 

 established by Cuvier (Eegue Animal, p. 319) in 1830. There is still doubt, 

 however, as to the exact identitj' of Cuvier's species. 



Wright and Studer (1., p. 154) give a detailed account of the history of 

 the name Scirpearia from the time of Cuvier to the time of publication of 

 the " Challenger " Eeport. 



In 1855 A''alenciennes (Comptes Eendus, xli., p. 14) established the 

 family Gorgonellaceae, with the following diagnosis : " Axis effervescing 

 with hydrochloric acid," to include two new genera, namely, Juncella and 

 Ctenocella. He defined them thus : — - 



Juncella — Stems straight, covered with polypiferous cells scattered upon 



the sclerobase. 

 Ctenocella — Sclerobase forming straight rods, pectinated only on one 



side of the principal stem. 



In the former genus he recognized the following new species : — J. juncea, 

 J. surcuhis, J. vimen, J. elongata, J. calyculata, and J. hystrix. 

 In the latter ('. 2^cctinata. 



Two years later Gray (P.Z.S., 1857, p. 159) proposed to re-arrange these 

 genera thus: "This genus Suberogoria) and the genera Juncella, Ctenocella, 

 and Gorgonella of Valenciennes should be arranged with Corallium under the 

 family Corallidae characterized by having a calcareous axis." In the same 

 year, however (P.Z.S., 1857, p. 287), he abolished the genus Ctenocella, divided 

 up the genus Juncella, established the genus EUisella, and gave the following 

 diagnoses and sulj-divisions to include one new and several previously 

 described species : — 



