184 Mr. S. 0. Eidley's Contributions to the 



XXII. — Contributions to the Knowledge of the Alcyonaria^ 

 with Descriptions of new Species from the Indian Ocean 

 and the Bay of Bengal. By Stuart O. Ridley, M.A., 

 F.L.S., Assistant in tlie Zoological Department, British 

 Museum. 



Of the new species which form the chief feature of this paper 

 two were recently obtained by a collector at Mauritius, Mr. 

 V. de Robillard, and purchased of him by the Trustees of the 

 Britisii Museum, and^ from their novel structural characters and 

 remarkable size and beauty, give great promise of important 

 results to be obtained whenever this little-known branch of 

 the fauna of Mauritius is more fully investigated. Extra- 

 ordinarily fine specimens of the beautiful Calligorgia (Prim- 

 noa) plumatilis^ M. lidw. & Haime, and the Hydrozoan 

 Stylaster flabelliformis^ were obtained from tlie same source. 



Notes are added on some of the genera of Gorgoniidse 

 established, mainly on external characters, by Dr. Gray ; the 

 types are in the British Museum, and have now been sub- 

 mitted to microscojDic examination. The results appear suffi- 

 ciently important to be worth recording, as many of these 

 genera can hardly be said to be known to science, owing to 

 tlie ignorance in which the descrijjtions leave us as to their 

 more minute characteristics. 



The measurements of spicules given below represent the 

 average maximum sizes of the spicules and are inclusive of 

 tubercles. 



AlctoninjEj Kolliker. 



Nephtiiya, Audouin. 



Nephthea, Audouin, E.xpl. pi. Descr. Eg3'pte, i. p. S.'jO. 



The only described species which can be admitted in this 

 genus, as distinguished from Ammothea by the large size of 

 its cortical spicules, from Eunephthya by their not projecting 

 from the surface of the coinenchyma, and from Spongodes by 

 the polype-spicules not projecting beyond the retracted polyj^e, 

 are : — 



N. Chabrolii, Audouin (inch innominata, Sav.), Expl. pi. 



Descr. Egypte, /. c. lied Sea. 

 N. {Alcyoniunij Q. & G.) aurantiaca^ Quoy & Gaimard, 

 Voy. Astrolabe, p. 277, pi. xxii. tigs. 16-18. New 

 Zealand. 

 N. coccinea, Stimpson, Proc. Acad. Philadelphia, vii. 

 p. o75. China. 



