. Birds of other lands, reptiles, fishes, jointed animals and lower forms;. Zoology; Birds; Reptiles; Fishes. SHELL-FISH, OR MOLLUSCS 345. Phola b, «'. Sj 'iIlc-Kinl, ] A SCORPION-SHELL Closely allied to the " Pelican i F"Ot ' [A/i.', Lcaf-gilled group. Though not so numerous in species as the last, it outrivals it in the enormous abundance in which the individuals of many varieties are produced. 0\'STERS, Mussels, Cockles, Scallops, and other allied forms occur in closely associated colonies, constituting natural " beds" or " banks," which may be
. Birds of other lands, reptiles, fishes, jointed animals and lower forms;. Zoology; Birds; Reptiles; Fishes. SHELL-FISH, OR MOLLUSCS 345. Phola b, «'. Sj 'iIlc-Kinl, ] A SCORPION-SHELL Closely allied to the " Pelican i F"Ot ' [A/i.', Lcaf-gilled group. Though not so numerous in species as the last, it outrivals it in the enormous abundance in which the individuals of many varieties are produced. 0\'STERS, Mussels, Cockles, Scallops, and other allied forms occur in closely associated colonies, constituting natural " beds" or " banks," which may be of vast extent and, in at any rate the case of oj'sters, several feet in thickness. From a commercial and economic standpoint this group is un- doubtedly of the highest importance to the human race. Not onl)' do its members, as instanced by the foregoing forms, contribute largely to the world's commissariat, they also yield the much-prized material known as " mother-of-pearl " and the purest and most aesthetically beautiful gems — orient pearls. Pearls and mother-of-pcail are the products of two groups of shell-fish, rcspcctivel}' known as and Pearl-MUssels. There are a consider- able number of species, mainly denizens of tropical seas, which, like ordinary oysters and mussels, occur naturally in banks and beds of vast extent. In some species, such as the Ceyl< iN Pe.\RL-(JYSTER, the shell is small, and the mother-of-pearl substance, or " nacre," as it is technically termed, so thin as to be of relati\-el\- little \-alue. Hence the fishery for this species is conducted almost exchisi\'el\- for the sake of the pearls, which are fairl}- numerous and frequentl}'of the finest quality. From the tropical Australian seas pearl-shells of the largest size, which produce the thickest and most \-aluable mother-of-pearl, are obtained. Pearls of the best quality are more rarel\' found in this description of shell, and its fishery is prosecuted prima
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Keywords: ., bookcentury1900, bookdecad, booksubjectfishes, booksubjectzoology
