SiJiPSON — A Revision of the GorgonelliJae. 7 



different specimens, so that it is almost certain that in this group the colonies 

 are dioecious. 



IV. — Historical Summary of the Group. 

 Family GORGONELLIDAE. 



The family Gorgonellidae is here regarded, on the wliolo, in the sense of 

 Wright and Studer (L, p. Ixiv), who, accepting Kolliker's diagnosis, define 

 it in the following terms : — • 



" In the species gf this family the coenenchyma is thin, smooth on the 

 surface, with small spicules in the form of warty double-clubs and stellate 

 forms. The polyps have more or less well-developed verrucae and are usually 

 biradially disposed. The axis is lamellar and calcareous, hut retains its 

 shape after the extraction of the calcareous matter." 



The colonies in the Gorgonellidae form simple or branched masses whose 

 calcareous axis gives to the whole a rigid appearance. The branches and 

 twigs are frequently flattened ; antl the polyps are either distributed in two 

 rows on the edges thereof, or are so disposed in lateral bands that a free 

 space is left in the middle, in which are to be found one or more longitudinal 

 furrows. The longitudinal canals are partly of snuill diameter, parti}' large. 

 Two usually occur on the surfaces of the stem wliieh are destitute of polyps. 

 On the surface of the coenenchyma in dried specimens their position is 

 marked by longitudinal grooves. 



It includes the following genera : — 



NiCELLA, .... Gray. 



SciiU'EAEiA, .... Cuvier, emend. Sliuler. 



SciRPEARELLA, . . . Wright and Studer. 



JuNCELLA,' .... Valenciennes, emend. Studer. 



Er.i.lSEi.LA, .... Gray, emend. Studer. 



Vehkucella, . . . Milne-Edwards. 



Ctenocella, . . . Valenciennes. 



I'HENILIA Gray. 



Heliania Gray. 



The two genera Phenilia and Heliania are only imperfectly known ; and 

 the diagnoses, as given by Gray, leave much to be desired. Stiuier considers 

 Piienilia as synonymous with Gorgonella ; and it is more than likely tiial 

 Heliania cannot now be con.sidered as a distinct genus. The spicules of 



' Theoriginal spelling of this genus was " Junceella," but it isnow gincrully wiiitrii " Junccllii," 

 so t)]at, except in references, the mure common spelling hua been adopted in this report. 



