On the Economical Uses of some species of Testacea. 257 



account of one which weighed five hundred and seven pounds ; the 

 largest valve measured four feet six inches in length, and two feet 

 five inches and a half in breadth, and one foot in depth. Large 

 pearls are occasionally found in them ; the same gentleman once 

 exhibited one which was valued at between nine hundred and twelve 

 hundred dollars ; a large shell of this sort is used as a baptismal 

 font in the church of St. Sulpice, at Paris, and was presented by the 

 Venetians to Francis the first. The shell is worked by the natives 

 of Sumatra into arm rings and other ornaments, and in ihe hands of 

 their artists is found to take a polish equal to finest statuary marble. 

 It is several inches thick, and perfectly white, and might probably 

 be used to advantage in some of the finer arts in this country. One 

 of the methods of taking them is by thrusting a long bamboo be- 

 tween the valves as they lie open, when by the immediate closure 

 that follows, they are made fast. The name for this shell in the 

 language of Sumatra is Kma, whence probably our word.* It is 

 this shell in which Neptune is represented in pictures to be riding. 



XXVII. Cameos or Camaieux, are in the present day frequently 

 made from shells. The word properly applies to the onyx stone, 

 whether cut or not, and which is formed of layers of different colors, 

 so that when cut the ground appears of one hue and the figure of 

 another. The derivation of the name is Camehuia, an oriental 

 word, signifying another stone, or one stone placed on another. The 

 shells employed are from the Mediterranean, but we have not been 

 able to ascertain the species — the genus we understand to be Venus. 

 The outer coat is white, the interior layers dark red, and being very 

 hard, admit of a fine polish. They are cut with the lapidary's mill. 

 The substitution of shells for stones, appears to be a very modern 

 invention. False cameos are made of pieces of glass of different 

 colors luted together, and afterwards either cut or cast, according to 

 the figure. It is these which are now so common and sold at so low 

 a price.f 



XXVIII. Shells have long been used by the ladies in making 

 fancy work ; sixty or seventy years since, this was particularly the 

 fashion in Europe, and large grottos, on which extravagant sums had 

 been expended were not uncommon, besides a multiplicity of fancy 



* Dilhvyn's Des. Cat. Vol. i. p. 215. Marsden's History of Sumatra, 3d ed. pp. 

 15, 121. 

 t Chalmers' Commercial Dictionary. Dictionnaire de Trevoux, Art. Onyx. 



Vol. XXXII.— No. 2. 33 



