Salenioida
# Salenioida

The Salenioida are an order of sea urchins.

## Description and characteristics

They are distinguished from other sea urchins by the presence of a large plate on the upper surface, with the anus to one side. They have very large tubercles between the ambulacral plates, and much smaller ones on the ambulacral plates themselves.

## Taxonomy

According to World Register of Marine Species :

* family Saleniidae L. Agassiz, 1838
* family Acrosaleniidae Gregory, 1900†
* family Goniophoridae Smith & Wright, 1990†
* family Hyposaleniidae Mortensen, 1934†
* family Pseudosaleniidae Vadet, 1999b†
