28 Proceedings of the Royal Irish Academy. 



that old but imperfectly known species, have necessitated the removal of the 

 Cape specimen from this genus. 



In many respects this colony is unique; and the writer has described it 

 separately as Dendrogorgia (n. g.) capensis, Proc. Eoy. Phys. Soc, Edin., 

 vol. xviii. (1910), p. 62. The following notes on the axis are of great 

 importance in this connexion : — . 



(1) The axis consists of concentric laminae. 



(2) These laminae are composed of a horny matrix, in which long 

 irregular spicules are embedded horizontally. 



(3) The horny substance preponderates in amount over the calcareous 

 matter, so that even with a lens the spicides are not very evident. 



(4) The spicules differ greatly in size and shape from those of the 

 coenenchyma. 



(5) Prolonged boiling in strong caustic potash results in a partial 

 separation of these spicules. 



(6) Wlien the coenenchyma is detached from the axis, a thin, white, trans- 

 parent film is generally found adherent to it. If this he peeled off and placed 

 under a microscope with a one-sixth objective, spicides identical with those of the 

 axis are seen embedded in it. 



From these facts it is at once evident that the axis in the case of this 

 specimen is distinctly sclerogorgic. It consists of spicules different from 

 those in the coenenchyma embedded in a horny matrix, the individual com- 

 ponents of which are laminae deposited concentrically; and, further, it is 

 possible to separate the outer layer, which is usually detached with the 

 coenenchyma. 



Juncella jtincea may be taken as a type of gorgonellid axis, and the 

 following are the chief points observed : — 



(1) The axis consists of a horny substance impregnated with lime. 



(2) The horny material greatly preponderates over the calcareous. 



(3) The axis is very hard, and is cut with difficulty. 



(4) It is impossible to see individual spicules either in a cross-section or 



a longitudinal section ; but 



(a) The axis is deposited in the form of concentric laminae. 



[I) A thin layer is usually found adherent to the detached coenenchyma, 



(c) This layer may be sepai'ated from the coenenchyma. 



(5) It contains small spicules not very unlike those of the coenenchyma, 



but different from them. 



