SHELLS USED FOR CAMEO-CUTTING. 699 



to this substance that the iridescent plumes of humming-birds, pheasants, and peacocks owe their 

 wonderful brilliancy. Murexide is now obtained not only from mollusks, but from guano, etc. 



Dyes from mollusks have been obtained in all ages and almost all quarters of the world, and 

 not only our Purpura lapillus, but also another species which we share with Great Britain, the 

 Whelk (Bucdnum undatum), have been the subject of successful experiments of this sort. " If the 

 shell of Pnrpxra lapillus is broken, there is seen on the back of the animal, under the skin, a 

 slender, longitudinal, whitish vein, containing a yellowish liquor. When this juice is applied to 

 linen, by means of a small brush, and exposed to the sun, it becomes green, blue, and purple, and 

 at last settles into a fine unchangeable crimson." The housewives of New England therefore have 

 growing abundantly on their sea-side rocks little living bottles of indelible ink which cannot be 

 excelled by any manufactured product for either beauty or durability, since neither acid nor alkali 

 will affect its color. 



On the Pacific coast occur shells of the genus Olivella, so called because they resemble small 

 olives. There are three species, Olivella biplicata, 0. gracilis, and 0. dam a. The first named of 

 these shells certainly, and possibly the other two, now and then were made into money by inany 

 Califoruian tribes of Indians, which money circulated widely on the Pacific slope. The common 

 Indian name for this Olivella money was "colcol." It was made by grinding off the apex or spire 

 of the shells in such a way that they could be strung. They are still used by some tribes in the 

 form of double necklaces as ornaments, but are regarded as of small value. Sometimes the shell 

 was broken crosswise and ground into little disks which passed as coins. This money was very 

 ancient and widespread through aboriginal traffic in connection with other forms of shell-money to be 

 mentioned hereafter, and which the present writer has fully discussed in a paper on "Wampum" 

 contained in the American Naturalist, 1 to which the reader is referred. 



Cameos are articles of ornament made by carving portions of various shells in such a way that 

 a raised figure of one color shall be relieved against a ground of another tint constituting the under 

 layer of the shell. These colors may vary white on an orange ground, or on dark claret; pale 

 salmon-color on orange ; yellow on pink, etc. Anciently cameos were cut upon gems with immense 

 labor, but latterly this easier imitation in shell has almost entirely superseded the intaglios in 

 onyx, agate, and jasper. The cameo artists live mostly in London and Paris, and use several 

 species of large shells that combine a white crust with a nacreous understratum of a different tint. 

 Two only of these shells come from American waters, and these only touch our coast in tropical 

 Florida Cassia madagaseariensis and Strombus gigas the ''Helmet-shell" and the "Couch." 



Of the Helmet-shell several sorts are used in cameo-catting. Our American example (which 

 got its name, mittliiunxcnricnxix, through an error in regard to the locality of the type-specimen) 

 has a blackish inner coat, called an "onyx" ground, and shows up white on a dark claret-color. 

 It is known to the trade as the Black Helmet, and is highly esteemed by cameo-cutters. 



The Conch or Queen Couch (Strombus gigaa) is of less account in cameo-making, because it 

 affords a less quantity of surface suitable for the work a portion of its broad, rose-tinted lip. 

 Various other ornaments are often made from this and other large shells by turning and sawing 

 with special machinery, and thus a large demand is created, which is satisfied chiefly through 

 brokers in London and Liverpool. Just how many shells are sent to England annually it is 

 impossible to tell; but the amount reaches some tens of thousands. There is also a large 

 commerce in them both to Europe and to the United States to be used as ornaments alone, and to 

 be given away by grocers and tea-dealers to promote their custom. In the West Indies, and on 



'American Naturalist, xvii, May, 1883, pp. 467-479. 



