Walcott, C. D. (1911). Middle Cambrian Holothurians and Medusae. In: Cambrian geology and paleontology. II. Smithsonian Miscellaneous Collections. 57(3): 41-68.
232000
Walcott, C. D.
1911
Middle Cambrian Holothurians and Medusae. In: Cambrian geology and paleontology. II