Squires, R. L.; Demetrion, R. A. (1995). A new genus of cassiduloid echinoid from the Lower Eocene of the Pacific Coast of Western North America and a new report of Cassidulus ellipticus Kew, 1920, from the Lower Eocene of Baja California Sur, Mexico. Journal of Paleontology. 69: 509-515.
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Squires, R. L.; Demetrion, R. A.
1995
A new genus of cassiduloid echinoid from the Lower Eocene of the Pacific Coast of Western North America and a new report of <i>Cassidulus ellipticus</i> Kew, 1920, from the Lower Eocene of Baja California Sur, Mexico.