Clark 1923. Scientific Results of the Expedition to the Gulf of California in Charge of C. H. Townsend, by the U. S. Fisheries Steamship" Albatross" in 1911. Commander G. H. Burrage, U. S. N., Commanding. XII. Echinoderms from Lower California, with Descriptions of Bulletin of the American Museum of Natural History, 48 1923: pp. 147-163