254 Proceedings of the Royal Irish Academy. 



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 pi-oblematical genera. 



It is extremely doubtful whether Yerrucella 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 witli regard to these forms. 



Excluding, then, Phenilia, Hcliania, Gorgonella, and Yerrucella, it might 

 be of advantage, before proceeding to examine and differentiate the ^'arious 

 "enera and sjjecies, to trace briefly the dillerent ba-sos 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 (Regne Animal, p. -"^If)) in IS.'^O. There is still doubt, 

 however, as t<j the exact identity of Cuvier's species. 



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

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

 the " Challenger " Hepurt. 



In 185.") Valenciennes (Comptes Eendus, xli., p. 14) established the 

 family Goi-gonellaceae, with the following diagnosis : " Axis efterve.scing 

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

 Ctenocella. He defined them thus : — 



Juncella — Stems straight, covered with polj'piferous cells scattered upon 



the sclerobase. 

 Ctksocklla — Sclerobase forming straight rods, pectinated only on one 



side of the principal stem. 



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

 J. siircuhu, J. rimcn, J. flongata, J, calyciilata, and J. hyslrix. 

 In the latter C. pcctinata. 



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

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

 and Gorgonella of Valenciennes should l)e 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 Ellisella, and gave the following 

 dif^^oses and sub-di\-i8ion8 to include one new and several previously 

 described species : — 



