May 1, 1899.] 



KNOWLEDGE. 



99 



Tahiti black-edged, they are now somewhat cheaper. A 

 large quantity go to Birmingham for manufacture into 

 buttons and counters, as well as for inlaying — the annual 

 imports, some years ago. oscillating between about three 

 thousand and five thousand hundredweights. 



Of other descriptions of pearl-oyster, ManUa shell, 

 which is fished from the great banks of these molluscs 

 stretching between the Sulu Islands, through the Strait of 

 Macassar, to BasUan, fetches prices not greatly inferior to 

 some of the Australian descriptions ; while Mergui shell, 

 from the archipelago of that name near the Tenasserim 

 coast, is somewhat cheaper, realizing from about five 

 pounds to eight pounds per hundredweight. Cheaper scUl 

 are the Banda, Panama, and Shark's Bay shell ; good 

 samples of the former varying from three pounds fifteen 

 shillings to four pounds five shillings, while similar 

 qualities of the latter range between one pound fifteen 

 shillings and two pounds sis shillings and sixpence. 

 Panama shells, which are small and black-edged, each 

 valve weighing only about half-a-pound, are obtained from 

 the Margarita, or Pearl Islands, in the Gulf of Panama. 

 Fair to good qualities sell at prices ranging from three 

 pounds to three pounds seven shillings and sixpence per 

 hundredweight, those fi-om the Island of St. .Joseph 

 being the best in quality. About 1855 the trade from 

 these islands began to be of importance, the annual 

 import for some years after that date ranging between 

 sixteen thousand and twenty thousand hundredweights. 



The foregoing are the chief descriptions of large pearl- 

 oysters employed in the mother-of-pearl trade ; and although 

 these constitute the great bulk of the industry, they by no 

 means include aU the commercial sources of that material. 

 Among several other kinds of shells, an important position 

 is held by a small species of pearl-oyster apparently 

 indistinguishable from the Ceylon M. fucata, and com- 

 mercially known as " lingah." These shells measure less 

 than three inches in diameter, and each valve averages 

 only about one ounce in weight. The great bulk of the 

 supply comes from the Persian Gulf, but a certain amount 

 is shipped from New Guinea. As it is imported and sold 

 in packages, the weight is not detailed, but as more than 

 twenty thousand packages were ofl'ered at a single sale in 

 1898, the total amount must be considerable. The price 

 of best quality varies from about twenty shillings to 

 thirty-five shillings per hundredweight, according to the 

 supply and demand. It is somewhat curious that this 

 shell should be valued, while the Ceylon pearl-oyster is 

 rejected. 



In the " M. 0. P." trade the term "mussel" has a 

 signification different from that in ordinary use, being 

 appUed to a species of true Aiicula, or those forms in 

 which the " wings " are conspicuously developed, and the 

 axis of the shell is very oblique. The particular species 

 used is the common A. heteroptem : usually the variety 

 in which the development of the hinder wing is compara- 

 tively small. "Bold and medium" shells may measure 

 between five and six inches in diameter, whereas 

 " chicken " shell is only between two and three inches. 

 The number of packages offered at one of Messrs. Lewis 

 and Peat's sales generally ranges between one hundred and 

 one thousand, the price per hundredweight varying 

 from two pounds thirteen shUlings to three pounds ten 

 shillings, or even four pounds, for the best quality. 



In addition to the foregoing, certain kinds of freshwater 

 mussels < Unionirlie , are used in the " M. 0. P." trade. 

 These are quoted as American sweet- water mussels, and 

 belong to the genera Paxyodon and Mutdti. When polished, 

 they present a pinMsh-white surface, with but little 

 pearly lustre. Both the supply and the demand seem to 



] be limited ; and no prices were quoted in 1898. Some 

 are worked up entire, while others are cut up. In the 



I United States there is a considerable manufacture of 



I ordinary pearl-buttons from freshwater mussel shells. 



I Turning to univalve shells, we find numerous quotations 

 of " Japan ear " in the trade-reports. This shell belongs 

 to the same genus ' Haliotisj as the much smaller ormer, or 

 ear-shell, found at low tide clinging to the rocks of the 



' shores of the Channel Islands, much after the manner of 

 a large flattened limpet. Indeed, the ear-shells are near 

 relatives of the keyhole-limpets (FisnurelUda), both show- 

 ing one or more perforations in the shell connected with 

 an excretory duct from the mantle. In the Haliotidm 

 these perforations form a curved line near the margin 

 furthest away from the short spire. Internally the whole 

 of the shell consists of a thick pearly layer, exhibiting a 

 beautifully iridescent play of colours. Some of the 

 tropical species measure from eight to ten inches across 

 the shell. Several of these, like the one from the South 

 Seas, have the shell so convex as to be of little or no 

 commercial value ; while in others, like the large Californian 



; species, although the shell is flatter, it is spoiled by the 

 great ridges and grooves on its outer surface. The Japan 

 ear-shell of commerce (Haliotis (liijantea) (Fig. "2), on 



Fig. 2. — Outer surface of " Japan Ear." 



the other hand, has a fairly flat and smooth shell, 

 characterised by the large size of the marginal per- 

 forations, which are raised into crater-like elevations. 

 As the portion of the shell external to the line of 

 perforations is useless, it is always broken away in 

 commercial specimens. Good samples of Japan ear in 

 this condition realize from about five pounds five shillings 

 to six pounds five shillings per hundredweight ; but 

 inferior descriptions sell as low as one pound five shillings. 

 Mother-of-pearl from ear-shells was formerly largely 

 employed at Birmingham for inlaying papier-maehe 

 ornaments and fancy goods, as it stiU is in America ; but 

 in this country it is now mainly used for studs, buttons, 

 links, buckles, etc., its opalescent green tints rendering it 

 more appreciated for some descriptions than the mother- 

 of-pearl from oysters. Occasionally pounded ear-shell is 

 used to ornament the lettering of shop-fronts. "Abalones" 

 is a commercial name for the mother-of-pearl from ear- 

 shells. 



Another shell of some importance in the trade is 



