Animal life in the sea and on the land . we must see themunder the sparkling water, where their beautiful formsand colors are heightened by The sun, and the sand, and the wild uproar. 10. How Pearls are Formed.—Pearls are formed in shellswhen grains of sand lodge between the mantle and the shelland become coated with the shelly matter, or nacre,which the mantle secretes. Fresh - water mussels yieldpearls that are sometimes quite valuable, but the finestpearls are obtained from the pearl-oyster. The pearl-oys-ter in Fig. 90 is the circular shell, which has a straighthinge and one pearl clinging
Animal life in the sea and on the land . we must see themunder the sparkling water, where their beautiful formsand colors are heightened by The sun, and the sand, and the wild uproar. 10. How Pearls are Formed.—Pearls are formed in shellswhen grains of sand lodge between the mantle and the shelland become coated with the shelly matter, or nacre,which the mantle secretes. Fresh - water mussels yieldpearls that are sometimes quite valuable, but the finestpearls are obtained from the pearl-oyster. The pearl-oys-ter in Fig. 90 is the circular shell, which has a straighthinge and one pearl clinging to it, and which is partly cov-ered by the mussel-shell. 11. Pearls mostly have a nucleus of sand in the centre,and the shelly layers are arranged around it like the coatsof an onion. The Chinese take advantage of this fact, andsometimes place small images or beads inside the shell,allowing them to remain until they are coated with of these are shown at the right of the picture. 152 ANIMAL LIFE IN THE SEA AND ON THE Fig. 90.—Pearl-bearing Shells. 12. Pearl Fisheries.—The most important pearl fisheriesare on the coast of Ceylon. The same locality is not fishedevery year for fear of impoverishing it. The labor of div-ing for pearl-oysters is very severe. The divers remain un-der water only thirty seconds at a time, but they sometimesdive twenty times in one morning, and become very muchexhausted. Having touched bottom, the diver gathers theoysters within reach, and places them in a net, then hepulls a cord as a signal to be drawn up immediately. Atmid-day a gun sounds for the fishing to stop, and the boatsare taken to the shore and unloaded before dark, in thepresence of officers, so that no robbing shall be done. 13. The oysters are allowed to remain on shore untilthey decompose. The pearls are then easily gatheredfrom the gaping shells, and they are worked with pow-dered nacre to give them a good polish. Pearls may beround, ovoid, or pear-shaped. Those
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1887
