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



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

 larger branches tliey are ranged more laterally. 1'he larger longitudinal vessels are 

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

 cylindrical twigs. The spicules are warty and needle-shaped spindles. 



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

 the former one, but it differs considerably in the nature of the spicules. Gorgonia 

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



3. Leptogorgia, Milne-Edwards, emend. Verrill. Milne-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 verrucae, and sometimes are completely retracted into the coenenchyma. They 

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

 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. Coenenchyma 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 polyps are scattered or disposed in two rows ; 

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

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

 inwards when at rest. 



5. CaUistephanus, n. gen. 



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

 horny and calcareous. Polyps very prominent, retractile within dome-like verrucse, 

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

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

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



6. Siviftia, 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 verrucge. The tentacles have spindle-shaped spicules, and 

 the spicules of the coenenchyma are scales. 



