1884.] species of oreaster. 65 



Triplacanthida. 

 a. Lophial and ventral spines. 

 westermanni. 



/3. Marginal spines also developed. 

 superbus. 



y. Dorsal spines also developed. 



gracilis. 



graiji. 

 orientalis. 

 troscheli. 

 muelleri. 



In the case of such species as I have been able to see I have given 

 a fresh description ; where specimens have been wanting, I have, in 

 the case of Dr. Lutken's forms, copied his Latin diagnoses, and for 

 other species I have drawn up brief diagnoses based on the descrip- 

 tions of preceding writers. 



Oreaster atjstralis. 



Oreaster australis, Liitken, Vidensk. Med. 1871, p. 263 

 (Australia). 



" Dorsum altum ; bruchia angusta, acuta, elongata ; radius stellce 

 major minor em triplum fere cequat ; tessellce marginales c. 21 ; 

 dorsales angulorum a margine paulum remotce ; tubcrcula 

 minuta singula in tessellis marginisventralibus plerumque adsunt, 

 in marginalibus dorsi angulorum vero perpauca, brachiorum 

 crebriora ; in tessellis dorsalibus propriis plerumque adsunt, 

 regidariter disposita, series quinas in brachiis formantia, media 

 tuberculis c. 13-14 majoribus gaudente ; intimum seriei cujus- 

 cunque omnium maximum ; arete poriferce confluentes, poris 

 numerosissimis ; tessellce vent rales propria granidatione obtectce, 

 haud conspicua:, granula minuta pedicellariasque numerosissimas 

 lineares elongatas gerunt ; papillae ambulacrales internee nonce, 

 externce ternce (rarius quatemce) ; papillae orales ori proximce 

 series singulas (non ut fieri solet duplicesj formant. 



Hab. ad oras Australise (Novse Hollandise)." 



Oreaster forcipulosus. 



Oreaster forcipulosus, Liitken, Vidensk. Med. 1864, p. 156. 



" Brachia angusta, acuminata; radius stellce major minor em 

 duplum cequat ; dorsum deplanatum nodosum ; tubercula vel 

 spince omnino mdlce in tessellis marginalibus, dorsalibus, ventra- 

 libusve, pedicellarice valvatce maxima: numerosissimce (7-15) 

 vero in omnibus hisce tessellis ; arece poriferce sexseriatce, sat 

 distinctce, poris c. 20 ; papilla ambulacrales externce 3 (2-4)." 



West Africa. 

 Proc. Zool. Soc— 1884, No. V. 5 



