Kingdom Animalia Class Echinoidea Rank Order | Phylum Echinodermata Subclass Perischoechinoidea | |
Similar Perischoechinoidea, Diadematacea, Cassiduloida, Gnathostomata, Holasteroida | ||
Echinocystitoida were an order of extinct sea urchin in the subclass Perischoechinoidea.
References
Echinocystitoida Wikipedia(Text) CC BY-SA