. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. Petaloconchus macrophragma.— Section across the shell at three periods of growth : a, one lamina first com- mencing, or ending; 6, upper lamina prolonged, lower commencing; c, upper lamina doubled over to meet the lower, while a rudimentary one appears between. * The operculum is a horny or shelly appendage to the end of the foot, drawn in last •when the animal retires into its shell, and thus protecting it. It may be called in com- mon lan
. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. Petaloconchus macrophragma.— Section across the shell at three periods of growth : a, one lamina first com- mencing, or ending; 6, upper lamina prolonged, lower commencing; c, upper lamina doubled over to meet the lower, while a rudimentary one appears between. * The operculum is a horny or shelly appendage to the end of the foot, drawn in last •when the animal retires into its shell, and thus protecting it. It may be called in com- mon language the trap-door or Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Smithsonian Institution. Board of Regents; United States National Museum. Report of the U. S. National Museum; Smithsonian Institution. Report of the Secretary. Washington : Smithsonian Institution
Size: 1474px × 1696px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorsmithsonianinstitutio, bookcentury1800, bookdecade1840
