The Echinoid Directory

Perischodomus biserials M'Coy, 1849; Sedwick Museum, Cambridge; syntype.  Lower Carboniferous, Hook Head, Ireland. Drawing of external  of the adapical surface. From Jackson, R. T. 1912. Phylogeny of the Echini, with a revision of Palaeozoic species Memoirs of the Boston Society of Natural History 7, 491 pp. 76 pls (pl. 64, fig. 7, 8)

Diameter of test fragment ca. 60 mm.