. Bulletin of the Southern California Academy of Sciences. Science; Natural history; Natural history. Bulletin, So. Calik. Acadimv ok Sciences Vol. 57, I'ait >, lOfiS. PLATE 38 Median longitudinal section of the shell, showing the internal spiral arrangement, columella, and aperture. A chitinoid disc on the muscular foot, the operculum, blocks the aperture. The operculum increases in width and depth with age, since during each growth period a new layer is added to the inner surface of the previous operculum. A cross-section reveals a series of individual layers each applied to the other, wi
. Bulletin of the Southern California Academy of Sciences. Science; Natural history; Natural history. Bulletin, So. Calik. Acadimv ok Sciences Vol. 57, I'ait >, lOfiS. PLATE 38 Median longitudinal section of the shell, showing the internal spiral arrangement, columella, and aperture. A chitinoid disc on the muscular foot, the operculum, blocks the aperture. The operculum increases in width and depth with age, since during each growth period a new layer is added to the inner surface of the previous operculum. A cross-section reveals a series of individual layers each applied to the other, with those of less diameter on the outer surface. Since this growth appears concentric around a central mass, the operculum is nucleate. 130. 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 Southern California Academy of Sciences. Los Angeles, Calif. : The Academy
Size: 1177px × 2123px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, books, booksubjectnaturalhistory
