1884.] species of oreaster. 65 



Triplacanthida. 

 a. Lophial and ventral spines. 

 zvestertnanni. 



/3. Marginal spines also developed. 

 superbics. 



y. Dorsal spines also developed. 



gracilis. 



grayi. 



orientalis. 



troscheli. 



muelleri. 



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

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

 the case of Dr. Liitken'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 australis. 



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

 ( Australia). 



" Dorsum altum ; bruchia a7igusta, acuta, elongata ; radius stellce 

 major minorem triplum fere cequat ; tessellce marginales c. 2\ ; 

 dorsales angulorum a margine paulum remotce ; tubercula 

 minuta singula in tessellis marginisventralibus j)lerumque adsunt, 

 in marginalibus dorsi angulorum vero perpauca, brachiorum 

 crebriora ; in tessellis dorsalibus propriis plerumque adsunt, 

 regulariter disposita, series quinas in brachiis formantia, media 

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

 cunque omnium maximum ; arece poriferte confluentes, poris 

 numerosissimis ; tessellce ventrales propria granulatione obtectce, 

 haud conspicuce, granula minuta pedicellariasque numerosissimas 

 lineares elongatas gerunt ; papillce ambulacrales internee nonce, 

 externce ternce (rarius quaternce) ; papillce orales ori proximce 

 series singulas (non ut fieri solet duplicesj formant. 



Hab. ad oras Australiae (Novse Hollandise)." 



Oreaster forcipulosus. 



Oreaster for cipulosus, Liitken, Vidensk. Med. 1864, p. 156. 



" Brachia angusta, acuminata; radius stellce major minorem 

 duplum cequat ; dorsum deplanatum nodosum ; tubercula vel 

 spitice omnino millcB in tessellis marginalibus, dorsalibus, ventra- 

 libusve, pedicellai-ice valvatce maximal numerosissimce (7-15) 

 vero in omnibus hisce tessellis ; arece poriferce sexseriatce, sat 

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



West Africa. 



Proc. Zool. Soc— 1884, No. V. 5 



