. The animals and man; an elementary textbook of zoology and human physiology. Zoology; Physiology. ARTHROPODS AND MOLLUSCS fjs superposed thin plates of shell material. Pearls are simply- isolated deposits of shell material usually around some particle of foreign substance which has found lodging in the mantle-cavity. Sometimes small objects are pur- posely introduced into the shell in order to stimulate the formation of pearls. The pearl-fishers go out in boats and. Fig. 86. Martesia xylophaga, a Pholad, burrowing in Panama mahogany. (Photograph by C. H. Snow; permission of the American Soci
. The animals and man; an elementary textbook of zoology and human physiology. Zoology; Physiology. ARTHROPODS AND MOLLUSCS fjs superposed thin plates of shell material. Pearls are simply- isolated deposits of shell material usually around some particle of foreign substance which has found lodging in the mantle-cavity. Sometimes small objects are pur- posely introduced into the shell in order to stimulate the formation of pearls. The pearl-fishers go out in boats and. Fig. 86. Martesia xylophaga, a Pholad, burrowing in Panama mahogany. (Photograph by C. H. Snow; permission of the American Society of Civil Engineers.) dive to the bottom, filling baskets with pearl-oysters. These are piled up in a bin and left to die and decompose. When the flesh is pretty thoroughly disintegrated, it is washed away with water, great care being taken that none of the pearls loose in the flesh are lost. When the washing is concluded the shells themselves are examined for pearls which may be attached to the interior of the valves. The principal pearl-fishery is that on the coast of Ceylon; pearl-fishing has been carried on here for over 2000 years. The ship-worm (Teredo) is an interesting member of this class of bivalve molluscs, because of its unusual habits, and strangely modified body form. The teredo is long and worm-like in general appearance, with a small bivalve shell at one end and two elongated siphons at the other. The. 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 Kellogg, Vernon L. (Vernon Lyman), 1867-1937; McCracken, Mary Isabel. New York, H. Holt and Company
Size: 2163px × 1155px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookd, booksubjectphysiology, booksubjectzoology
