Ix THE VOYAGE OF H.M.S. CHALLENGER. 



Family X. G o R G o JJ i D .e. 



Gorgonidse, Dana (pro parte). Zoophytes, p. 65 L 



Gorgoniaceie, Milne-Edwards (pro parte), Hist. Nat. des Coralliaires, t. i. p. 144. 



Gorgoniacex, Kcilliker (pro parte), Icones histiologicae, pt. ii. p. 139. 



Gorgonidx, Verrill, Trans. Connect. Acad., voL i. p. 386, and footnote (reprint), 1869. 



The colonies are upright and branched, usually in one plane. The axis is horny, 

 rarely horny and calcareous. The polyps arise from the stem and twigs in a bilateral or 

 biradiate manner, and a corresponding symmetry may also be observed in the canalicular 

 system. The anterior portion of each polyp is retractile either into projecting calyces or 

 into the coenenchyma. The latter has externally a smooth appearance. The spicules 

 are small, predominantly spindle-shaped, and are not disposed in two layers. 



KoUiker ^ was the first to employ characters drawn from the spicules for the revision of 

 the numerous genera into which Milne-Edwards had divided up the old genus Gorgonia, 

 Auct. He showed that among the species of the genera Leptogorgia, Lophogorgia, 

 Pterogorgia, Xip)higorgia, Rliipidogorgia, Hymenogorgia, Phyllogorgia, Phycogorgia, 

 and in part Gorgonia, many exhibited in regard to their spicules a great resemblance, but 

 that others, e.g., some species of Pterogorgia, Leptogorgia, and Rhipidogorgia, showed 

 such dissimilarity that they had to be referred even to distinct families. The allied species 

 he united into a single genus, for which he retained the old name Gorgonia, of which, 

 according to the form of the spicules, Kolliker distinguished three divisions. First, 

 those which had only spindles ; second, those which had both spindle-shaped and 

 scaphoid spicules ; third, those which have spindles, and in addition a special cortical 

 layer of clubs. 



Verrill ^ agrees generally with the conclusions of Kolliker, but differs in distinguishing 

 the three divisions as so many independent genera. For the first division, the species of 

 which are spindles only, the name Litigorgia, afterwards that of Leptogorgia, was 

 proposed ; for the second, with spindles and scaphoids, the name Pterogorgia, and 

 subsequently Gorgonia was proposed ; while for the third division, the name Gorgonia, 

 and subsequently Eunicella, was given. To these three there was added a fourth 

 genus {Eugorgia), in which the spicules were double spindles and double wheels. 

 In the memoir cited it was shown by Verrill that Eunicella should be placed in nearer 

 relationship with the Plexauridse, and to this family Verrill subsequently^ referred the 

 genus. However natural and easily understood is such a distinction of genera, yet 

 this subdivision of this family can be based on other characters in addition to the 

 form of the spicules. 



Among the Gorgonidx one may observe in the disposition of the polyps a tendency 

 towards a biradial arrangement. The same thing is indicated even in the form of the 



1 Icones histiologicEe, pt. ii. p. 139. - Notes on Eadiata, Trans. Connect. Acad., vol. i. p. 384. 



^ Amer. Journ. Sci. and Arts, vol. xlviii. p. 425, 1869. 



