Plexechinus Agassiz 1898

Agassiz 1898. Reports on the dredging operations off the west coast of Central America to the Galapagos, to the west coast of Mexico, and in the Gulf of California, in steamer "Albatross," &c. xxiii. Preliminary Report on the Echini. Bulletin of the Museum at Harvard College, xxxii(No. 5) 1898: pp. 71-86