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1b. Peristomial membrane formed of a series of uniform, wedge-shaped ambulacral plates. |
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2b. Primary spines simple, without a terminal hyaline hoof. Ambulacral pore-pairs forming a single irregular column in each series. |
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3b. Ambulacra with uniserial pores adorally; primary tubercles not heterogeneous and not creating multicompound elements (peristome edge at far right). |
4a. Ambulacra with major element in each pseudocompound plate excluded from the adradial suture in ambital and adapical plates. |
4b. Ambulacra with major element in each pseudocompound plate reaching adradial suture. |