The Echinoid Directory

Family Plexechinidae Mooi & David, 1996, p. 946


 Urechinine holasteroids with:

  • thin test;
  • orthosternous plastron (labral plate followed by single symmetrical sternal plate). Labral plate may be separated from sternal plate by ambulacral plates;
  • ambulacral plates I.a.4 and V.b.4 extended behind episternal plates and incorporated into subanal fasciole;
  • no rostral plate;
  • pores outside phyllodes single;
  • apical disc with single anterior genital plate;
  • periproct supramarginal; somewhat sunken.
Recent; Indo-Pacific, Antarctic.