562 



TIIK VOYAGE OF H.M.S. CHALLENGER. 



b. Monacanthid : Armature of the adambulacral plates consist- 

 ing of one spine, 

 a. Abactinal spinelets isolated, with large pedicellaria? in- 

 terspersed ........ 



b. Pentactinid : Having five rays. 



a. Diplacanthid : Armature of the adambulacral plates consist- 

 ing of two spines. 

 a. Spiniferous actinal plates contingent on the adambul- 

 acral plates, and bearing an oblique series of three 

 spinelets. Spinelets generally with a high-mount- 

 ing, abruptly-terminating sheath of membrane sur- 

 mounted by a wreath of pedicellaria? 

 ft. Spiniferous actinal plates well spaced from the adam- 

 bulacral plates, and bearing only one or two 

 spinelets. 

 i. With a vertical lateral wall. 



1. Abactinal spines with vesiculated pedicel- 



laria?, forming tuft-like groups. Arma- 

 ture of the adambulacral plates regularly 

 diplacanthid ..... 



2. Abactinal spines not surrounded by vesicu- 



lated pedicellarise, and, though pedicel- 

 larise are numerous, they do not form 

 tuft-like groups. Armature of the ad- 

 ambulacral plates alternately or irregu- 

 larly diplacanthid and monacanthid 

 ii. With an angular margin. Abactinal spines 



isolated. Pedicellariae not vesiculated and 



more or less distributed. 



1. Supero-marginal plates with a single longi- 



tudinal series of spines 



2. Supero-marginal plates with a grouped series 



of spines ...... 



b. Monacanthid : Armature of the adambulacral plates consist- 

 ing of one spine. 

 a. Abactinal spinelets isolated, and having large isolated 

 forcipiform pedicellarias interspersed 

 Aeferias sold/era group : Several series of actinal intermediate plates pre- 

 sent, bearing spinelets which form regular longitudinal and transverse 

 series. Madreporiform body echinoplacid (Bell) . . Sub-gen. 



a. Abactinal spines vesiculated. Numerous large forficiform pedicellaria; 



on the abactinal surface ........ 



b. Abactinal spines not vesiculated. Forficiform pedicellaria?. absent on the 



abactinal surface or of rare occurrence and not remarkably large . 

 Arferias gcaljmfera group : Armature of the adambulacral and infero- 

 marginal plates consisting of flattened spines, forming transversely or 

 obliquely placed combs. Abactinal plating forming a sub-compact 

 network. Spinelets numerous and grouped . . . Sub-gen. 

 a. Armature of the adambulacral plates consisting of three spines. In- 

 fero-marginal plates with oblique combs of four spines . 



pemeri. 



torquata. 



glomerafa. 



rubens. 



versicolor. 

 amurensis. 



. cunninohami. 



CoSMASTERIAS. 



tomidata. 

 sulcifera. 



Smilasterias. 



. scalprifera. 



