Cassidulidae Agassiz and Desor, 1847
Common Name: Sea urchin
Key morphological features: Test is small to large in size. External petal shapes are broad and equal in shape.
MOBILITY: Mobile (burrow, crawl)
FEEDING MODE: Detritivore
Fell, H. B. and Pawson, L. P., 1966. Systematic Descriptions, in R. C. Moore ed., Treatise on Invertebrate Paleontology, Part U, Echinodermata 3, Volume 2. The University of Kansas and Geological Society of America. 695 pp.