238 



MR. S. O. RIDLEY ON ALCTONARTA 



are present here, and spicule No. 4 is not represented in Psam- 

 mogorgia. On the other hand, it resembles Leptogorgia in the 

 form and tubercles of the elegant spicule No. 2. 



Gorgqnia*, sens, strict. 



(Grorgonia, sens, mod., Verrill, Amer. Journ. Science, (2) xlviii. 

 p. 424.) 



The "Klammer" type of spicule ("bracket- or crescent-shaped," 

 Verrill, I. c. • " scaphoid," Kent, Monthly Microsc. Journ. in. 

 1870, p. 90), by which this section of Gorgonaceans is charac- 

 terized by KoJliker and Verrill, is developed in various degrees 

 of definiteness, and. besides being pretty obviously only a 

 modification of the regular fusiform type prevailing in this and 

 the allied genera, differs but slightly from it in some species, as 

 in the one now to be described ; hence the difference between 

 Gorgonia and Leptogorgia (Verrill) becomes but a slight one. 

 Still the genera should perhaps be maintained distinct, if only to 

 preserve order among the numerous species composing the 

 group. Gorgonia, however, unites types characterized by very 

 diverse external forms (e. g. Hymenogorgia, Xiphigorgia, Ptero- 

 gorgia, Phipidigorgia) ; but there is at any rate one probably 

 natural group among them, viz. the pinnately branched form 

 (JPterogorgia). 



Gorgonia oppositipinna, n. sp. (Plate XVIII. figs. 7-11.) 



Corallum erect, ramose, typically flabelliform. Base very 

 narrow. Stem (in single specimen) very short. Mode of 

 branching after the fir.-t division almost wholly oppositely 

 pinnate, tending to become alternately pinnate towards the 

 periphery ; pinnae in lower part of colony about ^ inch apart, 

 towards periphery up to about 2 inches ; terminal pinnae up to 

 3 inches in length. Pinnae given off at angles of about 65° in 



* Note.— I take this opportunity of correcting an error into which I fell 

 in llic description of the Alcyonaria brought home by II. M.S. ' Alert' (Report 

 Zool.OolL H.M.S. ' Alert,' London, 1881;. Leptogorgia amtraliensis, raihi (loc. 

 tit. p. #42, pi. xxxvi. figs, c, c', (',<■'), should stand as Gorgonia audraliemis, for 

 the following reason. It occurred to me, on considering the pinnate arrange- 

 ment of the branches, to re-examine the spicules to sec whether I had possibly 

 overlooked, from its resemblance to the Uniform, the occurrence of a scaphoid 

 spicule here ; I found it to be bo. The scaphoids of G. australimds are closely 

 similar to those here figured for G. oppositipinna, indeed the long ones are 

 practically identical with those of that species. 



