Robuta

https://rmcg.unam.mx/index.php/rmcg/article/view/1214 Fossil Encope (Echinoidea) from the Pacific coast of southern Mexico | Revista Mexicana de Ciencias... https://repository.si.edu/items/3b635283-a90a-44db-b45d-657abd4fcc44/full Systematics and ecology of the sea urchin genus ICentrostephanus/I (Echinodermata: Echinoidea)... of the sea https://rmcg.unam.mx/index.php/rmcg/article/view/1214/1018 View of Fossil Encope (Echinoidea) from the Pacific coast of southern Mexico | Revista Mexicana de... https://dukespace.lib.duke.edu/items/396aba67-07e7-4ea1-b422-3aacbc228d4e/full Spatial vision in the purple sea urchin Strongylocentrotus purpuratus (Echinoidea). Recent evidence that echinoids of the genus Echinometra have moderate visual acuity that appears to be mediated by their spines screening off-axis light... spatial vision in the purple sea urchin echinoidea