and the tentacle bases are beset with spicules. The spicules are almost always girdled forms, 

 i. e. with a median band which is bare of verrucee, and hence appear to have an impressed 

 girdle. This results in the formation of double heads, double clubs, double spindles, double 

 stars, etc. ; and these forms are quite characteristic of the Gorgonellidse, although not strictly 

 confined to this family. 



Dichromatism is exhibited in a marked degree, a number of species of yinicclla and 

 Scipearella being characterized by having two color phases, red and white, which do not 

 appear to be corellated with sex or age. 



The systematic arrangement of this family offers great difficulties, as is apt to be the 

 case with forms which have been long known. The original descriptions are entirely inadequate, 

 and it is usually impracticable to decide just what forms the authors had before them. None 

 of them paid any attention to the feature that has later been found of prime importance in 

 generic definitions, e. g. the spicules, and confined themselves almost exclusively to general 

 habit, mode of branching, etc., features of almost no generic import whatever. Subsequent 

 writers have ver\' generally neglected the discussion of the genera in any broad way. 



MiLXE Edw.'vrds and Haime (1857) recognize the four genera Jjincclla^ Cicnocclla^ 

 Gorgonella and Verrucc/Ia, which they separated by modes of branching and character of the 

 calyces. Kölliker (1865) was the first to thoroughly investigate the spicules of this family, and 

 he recognized the genera Gorgonella, yjincclla and Verrtuclla ; but included the genus Riisca 

 of DucHASS.\iNG and Michelotti, which apj^ears to belong to the family Chrysogorgidae. He 

 includes the genus Ctenocella in his genus Gorgo7iclla. 



Gray (1870) divides the genus ytincella into the three genera Juncella, Ellisella and Vivie- 

 nclla and restores the genus Scirpcarea. He established the genera Nicella, Rcticella, Raynerclla^ 

 Phenella and Hcliana. Two of these, Reticella and Raynerella, appear to belong to Goi'gonella. 



Studer, (1878) discusses and further defines the genera Gorgonella, Juncclla, Ellisella, 

 Ctenocella and Scirpearella-, and in 1887 the same writer gives a careful discussion of the 

 genera of this family, defining according to modern methods the following genera : Xicella, 

 Scirpcarea, yiincella, Ellisella, Verrticella, Gorgonella, Ctenocella, Phcnclia and Heliana. The 

 last two of these genera he defines after Gray without giving the spicule characters which are 

 absolutely necessary for modern definition. This treatment is the most satisfactory that has yet 

 been presented, and the generic definitions here given are very largely adopted without essential' 

 modification by the present writer. 



The last general treatment of the family GorgonellidEe as a whole is found in Wright and 

 Studer's Challenger Report, Alcyonaria, 1889, p. 153, where the definitions of Studer, as just 

 discussed, are practically adopted in their entirety. They add, however, one genus, Scirpcarella 

 and throw doubt on the identity and validity of the old genus Scirpcarea of Cuvier, quoting 

 the discussion of Scirpcarea »lirabilis by Kolliker ' who shows that the name was originally 

 used for a pennatulid. 



Thomson and Simpson, in their excellent monograph of the Alcyonaria secured by the 



' Anat.-Syst. Beschr. der Alcyonaiien, Die PennaUilidcn, 1872, p. 26. 



