original description(ofMegistostoma Gabb, 1864 †)Gabb, W. M. (1864). Description of the Cretaceous fossils. <em>In: Meek, F. B. and Gabb, W. M. Geological Survey of California, Palaeontology of California.</em> 1: 55-243, pls. 9-32., available online athttps://biodiversitylibrary.org/page/2062749 page(s): 144 [details]