. Juvenile Instructor. Figure 10. shell of pcurl oyster ( coiitiilnliif; olijoets eovcn^d with peurl. 438 THE JUVENILE INSTRUCTOR. commerce, which rank among the mostcostly of jewels. It is possible toincrease the supply of pearls by a semi-artificial process which has been fol-lowed by the Chinese and other orientalnations for centuries. They take the. Figure 11. Thi>rny oyster {.Spondi/his ngiiis), pearl oysters from the water, force theshell partly open, and place withinthem tiny objects which they wishtransformed into pearls; the bivalvesare then returned to the water. Afte
. Juvenile Instructor. Figure 10. shell of pcurl oyster ( coiitiilnliif; olijoets eovcn^d with peurl. 438 THE JUVENILE INSTRUCTOR. commerce, which rank among the mostcostly of jewels. It is possible toincrease the supply of pearls by a semi-artificial process which has been fol-lowed by the Chinese and other orientalnations for centuries. They take the. Figure 11. Thi>rny oyster {.Spondi/his ngiiis), pearl oysters from the water, force theshell partly open, and place withinthem tiny objects which they wishtransformed into pearls; the bivalvesare then returned to the water. Aftera few months they are opened again,and the pearls are removed. Figure 10 Figure 12. HiuiiiiuT Oyster. (.Mallnts lulgaris). shows the valves of an oyster contain- | ing tiny balls of pearl, and a number [of images, — representing oriental idols, all coated with pearly nacre. I Figure 11 shows a species of Spondylus,one of the Thorny Oysters, so namedfrom the spiny exterior of the spines are extremely fragile, andperfect specimens are rare in the cabi-nets of naturalists. Thorny oysters arefound in the waters about the WestIndies, as also in the Mediterraneanand off the coasts of India. Several varieties of the HammerOyster are known in eastern 12 shows one of the commonestforms. In this the ring-like expansionsare greatl) developed
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Keywords: ., bookauthorgeorgequaylecannon182, bookcentury1800, bookdecade1890
