Crinoid

Ptychocrinus splendens

• Ordovician
• Girardeau Formation
• Cape Girardeau, Missouri, USA

Size: 4 cm crown

Diagnosis indicates "stellate ridges on the iBrr of adults; arms branching on iiBrr13 to 15; arms commonly bifurcate again on iiiBrr30 to 40." (Brower 1972)