The Echinoid Directory

Spatagocystis A. Agassiz, 1879, p. 206

Diagnostic Features
  • Test medium-sized, ovate; paper-thin shell.
  • Apical disc with anterior genital plates fused; four gonopores.
  • Ambulacra all similar with minute pore-pairs only; all flush.
  • Peristome circular and deeply invaginated; opening into anterior groove.
  • Plastron plating orthosternous and disjunct. Episternal plates opposite; subsequent plating tending to be biserial.
  • Scattered primary tubercles uniformly distributed over the entire aboral surface.
  • Periproct submarginal to oral with strong subanal heel; invaginated.
  • Subanal fasciole present in at least some individuals.
Recent; Antarctic Ocean.
Name gender feminine
Spatagocystis challengeri A. Agassiz, 1879, p. 206, by original designation.
Species Included
  • Only the type species.
Classification and/or Status

Holasteroida, Meridosternata, Urechinina, Pourtalesiidae.



Differs from Pourtalesia in having a much less developed subanal heel. In Pourtalesia the periproct is supraambital, whereas in Spatagocystis it is marginal to inframarginal.

Agassiz, A. 1879. Preliminary report on teh Echini of the Exploring Expedition H. M. S. Challenger Sir C. Wyville Thomson Chief of Civilian Staff. Proceedings of the American Academy of Arts and Science 14, 182-261,

A. Agassiz 1904. Reports on an exploration off the West coasts of Mexico, Central and South America, and off th Galapagos Islands 32, The Panamic deep sea echinoids. Memoirs of Museum of Comparative Zoology, Harvard 31