90 PTERASTERIDAE. 



B.i No true suboral spines though the innermost of the 3 orals might be so considered trios. 



BB.' Suboral spines present. 



C.^ No small marginal spines on oral plates. 



D.^ 3 large, subequal spines on each oral plate (all suborals or 2 suborals + 1 oral) edax. 



DD.2 2 large spines on each oral plate (both suborals or 1 suboral + 1 oral). 



E'. Valves of osculum with 5 or 6 spines; paxillae with 5-8 spinelets; color yellowish white. 



campanulatus. 

 EE.' Valves of osculum with 10 spines; paxUlae with 4 spinelets; color dark or at least dusky. 



purpureus. 

 CC Marginal spines (orals), smaller than suborals, present on oral plates. 

 D.' Suboral spine single. 

 E.2 Adambulacral spines 2; membranes fleshy; spiracula very small and grouped; orals 4-6. 



F. Suboral spine like a segmental papilla pentagonalis. 



FF. Suboral spine not like a segmental papilla carnosus. 



EE.^ Adambulacral spines more than 2. 



F.i Rays attenuate, R = about 2 r; adambulacral .spines 3 geometricus. 



FF.i Rays not at all attenuate. 



G. Orals 3, stout; tliird or fourth actinolateral spine longest coccinatus. 



GG. Orals 4 or 5, slender. 



H. Fifth or si.xth actinolateral spine longest; adambulacral spines 3 or 4, not in a 



continuous series modestus. 



HH. Seventh to eleventh actinolateral spines longest; adambulacral spines 4 or 5 in a 



continuous series quadrispinosus. 



DD.' More than one suboral to a plate. 

 E.' Suboral spines 2 on each plate. 

 F.2 Only 2 adambulacral spines (3 on some plates, in ■perissonotus) . 



G.' Only 2 orals giboryi. 



GG.^ 3 or more orals. 



H.' Paxillar spinelets few, rarely more than 5, often 3. 

 I. Orals 3. 



J. Actinolateral spines rather short, robust, eighth or ninth longest . . . echinulatus. 

 JJ. Actinolateral spines very long, twentieth to twenty-second longest. 



II. Orals 4-7. 



J.' Of actinolateral spines, fifth to twelfth longest. 



K. More or less pentagonal; paxillar spinelets 4 or 5; orals 4 roseus. 



IvK. More or less stellate; paxillar spinelets usually 3; orals 5 agassizii. 



JJ.' Of actinolateral spines, twelfth to twenty-first longest. 



K.' Of actinolateral spines, twentieth or twenty-first longest sacculaius. 



KJC Of actinolateral spines, eighteenth or earlier longest. 



L. Paxillar areas of rays conspicuously elevated; actinolateral spines short, 



stout glaticus . 



LL. Paxillar areas not conspicuously elevated; actinolateral spines long, 

 slender. 

 M. Paxillar spinelets 3 or 4; on some plates, 3 adambulacral spines. 



perissonottis. 



MM. Paxillar spinelets 4-6; only 2 adambulacral spines vicarius. 



HH.' Paxillar spinelets many, 5-12. 



I.' Paxillar spinelets 5-7 pellucidus. 



II.» Paxillar spinelets 8-12. 



J.^ Form pentagonal perspicuus. 



JJ.^ Form stellate infernalis. 



FF.2 More than 2 adambulacral spines, except on individual plates or near tip of ray. 



G.'' Color deep purple, with fibrous bands in supradorsal membrane and tips of tube- 

 feet, white; adambulacral .spines 3, short, thick subequal pullatus.^ 



GG.' Not as above. 



H.' Orals 2; paxillar spinelets 5-7; adambulcral spinelets 3-5; fifth actinolateral 

 spine longest praecoquis. 



Sladen's figure shows 4 oral spines but in his description he distinctly says there are only two. 



