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



without spicules, at other times with numerous transparent glassy, fusiform, often 

 spiny spicules, or with irregular scale-like spicules ; sometimes the spicules are in two 

 layers. Polyps ; large, prominent, inserted on the axis either at right angles or 

 obliquely ; covered with spicules, variously arranged ; tentacles retractile, sometimes only 

 imperfectly so. 



1. Strophogorginse. — Simple unbranched axis. 



2. Chrysogorginae. — Branched axis. 



Subfamily 1. Strophogorgix^. 



Colony unbranched. The axis consists of a simple, calcareous, often brittle stem, 

 springing from a number of root-like processes ; sometimes erect, rigid, round ; sometimes 

 trailing. The ccenenchyma ; in some extremely thin, allowing the iridescent axis to 

 be seen through it, and furnished with few spicules ; at other times it is thick and 

 membranous, with numerous spicules. Polyps ; prominent and arranged in a uniserial 

 manner on the axis. The tentacles are retractile, forming by their basal portions 

 cjuasi-opercular coverings. The polyp bodies are covered with spicules, which are often 

 arranged towards the apices of the polyps in eight rows, eventually becoming smaller and 

 then being lost on the extremities of the dorsal surface of the tentacles. 



The spicules are translucent glass-like spindles or scales of irregular form ; the spindles 

 are sometimes smooth ; sometimes with roughened edges. 



Genus Sti'ophogorgia,^ Perceval Wright. 

 Stropliogorrjia, Perceval Wright, Narr. Chall. Exp., vol. i. pt. ii. p. 691, 1885. 

 Colony unbranched ; axis calcareous, erect or creeping ; iridescent. Base where 

 observed, calcareous, divided into diverging hard and brittle root-like structures for 

 anchoring the colony in the mud. 



The polyps are prominent and arranged in a uniserial manner on the axis, either 

 stalked or sessile. The ccenenchyma varies in thickness, being sometimes very thin, with 

 few spicules ; or membranous, with numerous spicules. 

 Four species are found in the collection. 



1. Strophogorgia petersi, n. sp. (PL II. figs. 1, la; PI. Va. fig. 1). 



Colony simple, unbranched. Axis calcareous, brittle, in some .specimens exceeding 

 6 dm. in length ; the basal portions with numerous, broad, rhizome-like processes, 

 from 3 mm. in diameter at the base to less than 1 mm. at theii' apices. 



