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



On the terminal twigs the polyps are distributed over the whole periphery; on the 

 larger branches they are ranged more laterally. The larger longi/udinal vessels are 

 distributed over the flattened portions of the axis but are placed peripherally on the 

 cylindrical twigs. The spicules are w^arty and needle-shaped spindles. 



In general habit and in the nature of the ccenenchyma this genus is closely allied to 

 the former one, but it difi"ers considerably in the nature of the spicules. Gorgonia 

 Jlammea, Ellis and Solander, and Lophogorgia cristata, Mobius, are representative forms. 



3. Leptogorgia, Milne-Edwards, emend. Verrill. MUne-Edwards, Hist. Nat. des 



Coralliaires, t. i. p. 163 {ex parte); emend. Verrill, Trans. Connect. Acad., 

 vol. i. p. 387. 



The colony varies greatly in form, but is more or less ramified in one plane. It often 

 exhibits a net-like structure from an anastomosis of the branches. The polyps sometimes 

 form short verrucas, and sometimes are completely retracted into the ccenenchyma. They 

 are usually disposed in two lateral rows, having between them the naked ccenenchyma. 

 Upon the surface of the latter the courses of the larger tubes are indicated by longitudinal 

 depressions. 



The spicules are usually minute double spindles of variable length. 



4. Stenogorgia, Verrill, Bull. Mus. Comp. Zool., vol. xi. p. 29, No. 1, 1883. 



The colony is branched, axis horny. Ccenenchyma thin, with small warty spindle- 

 shaped spicules, and on the surface a few smaller, short, irregular, rough, granular spicules, 

 which do not form a complete layer. The pol}'ps are scattered or disposed in two rows ; 

 they project from the surface. The polyp spicules are like those of the ccenenchyma, 

 but in the tentacles spindle-shaped spicules occur. The polyps are retractile and are bent 

 inwards when at rest. 



5. CalUstephanus, n. gen. 



The colony is feebly branched, branches arising in the one plane at right angles, axis 

 horny and calcareous. Polj'ps very prominent, retractile within dome-like verrucse, 

 arising for the most part from the sides of the stem and branches. The ccenenchyma is 

 thick, granular. The spicules of the ccenenchyma are spiny spindles, clubs, and half- 

 sided warty clubs. At the base of the polyps the spicules are needle-shaped. 



6. Siciftia, Duchassaing and Michelotti, Suppl. Mem. Corall. des Antilles, 1864, p. 13. 



The colony is upright, ramified with a horny, calcareous axis (?). Polyps at either 

 side of the branches, within verrucse. The tentacles have spindle-shaped spicules, and 

 the spicules of the ccenenchyma are scales. 



