Arnold, R. (1903). The paleontology and stratigraphy of the marine Pliocene and Pleistocene of San Pedro, California. <em>Memoirs of the California Academy of Sciences.</em> 3: 1-420., available online athttps://www.biodiversitylibrary.org/page/3136160 page(s): 285, pl. 4 fig. 14 [details]
original descriptionArnold, R. (1903). The paleontology and stratigraphy of the marine Pliocene and Pleistocene of San Pedro, California. <em>Memoirs of the California Academy of Sciences.</em> 3: 1-420., available online athttps://www.biodiversitylibrary.org/page/3136160 page(s): 285, pl. 4 fig. 14 [details]