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The Echinoid Directory

Infraorder Laganiformes Desor, 1857, p. 217

Diagnosis

 Clypeasteroids with:

  • lantern muscle attachment points formed of five single (fused) pegs that are interradial in position;
  • interambulacral zones narrow and uninterrupted; ending adapically in one or more single plates;
  • periproct oral, generally opening between the first and second paired post-basicoronal plates.
Range
 Eocene to Recent; worldwide.
Remarks

Scutelliformes have a similar perignathic girdle but never have interambulacra ending adapically in a single plate.

The following taxon is too poorly known to place to family

Runa Agassiz, 1841