562 THE VOYAGE OF H.M.S. CHALLENGER. 
b. Monacanthid: Armature of the adambulacral plates consist- 
ing of one spine. 
a, Abactinal spinelets isolated, with large pedicellariz in- 
terspersed . 0 7 5 5 ° . . . pervert. 
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 pedicellarie . : 0 torquata. 
B. Spiniferous actinal plates well spaced from the diene 
bulacral plates, and bearing only one or two 
spinelets. 
i, With a vertical lateral wall. 
1. Abactinal spines with vesiculated pedicel- 
larie, forming tuft-like groups. Arma- 
ture of the adambulacral plates ay 
diplacanthid : : : 3 glomerata. 
. Abactinal spines not surrounded ne vesicu- 
lated pedicellariz, and, though pedicel- 
lari are numerous, they do not form 
tuft-like groups. Armature of the ad- 
ambulacral plates alternately or irregu- 
larly diplacanthid and monacanthid . : rubens. 
ii. With an angular margin. Abactinal spines 
isolated. Pedicellariz not vesiculated and 
more or less distributed. 
1. Supero-marginal plates with a single longi- 
tudinal series of spines : : S : versicolor. 
2. Supero-marginal plates with a grouped series 
of spines, . . . : amurensis, 
b. Monacanthid: Armature of the adamibalacral plates pone 
ing of one spine. 
«, Abactinal spinelets isolated, and having large isolated 
forcipiform pedicellariz interspersed —. : J ° cunningham, 
B, Asterias sulcifera group: Several series of actinal intermediate plates pre- 
sent, bearing spinelets which form regular longitudinal and transverse 
series. Madreporiform body echinoplacid (Bell) 6 - Sub-gen, CosMAsTERIas. 
a. Abactinal spines vesiculated. Numerous large forficiform pedicellarize 
on the abactinal surface . . 0 é : : c 0 : tomidata. 
b. Abactinal spines not vesiculated. Forficiform pedicellarie absent on the 
abactinal surface or of rare occurrence and not remarkably large . . suletfera. 
C. Asterias scalprifera 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 =. 6 0 Sub-gen. SMILASTERIAS. 
a, Armature of the adambulacral plates consisting of three spines. In- 
fero-marginal plates with oblique combs of four spines. ° ° scalprifera. 
