302 The Commercial Products of the Sea. 



graved in German text, old English, Roman, and italic 

 characters. On the occasion of presenting the shell, a sum 

 of money was put into the hands of the artist ; and a few 

 days after, the poor man was astonished by the receipt of 

 a large packing-case, which, upon opening, he found to 

 contain a proof impression of Sir G. Hayter's " Coronation " 

 picture, framed and tastefully ornamented with the rose, 

 shamrock, and thistle in burnished and dead gold. 



The Chinese are very fond of having patterns carved 

 on the nautilus shell, while the body of the shell is uncoated 

 to show the nacre. 



The shell of an Anodonta is used for the bridge of 

 musical instruments by the Mittoo tribe in Africa, and 

 round fragments of shell are used by them for gambling 

 purposes. In Japan the ladies play a game with the valves 

 of shells with painted designs on them. 



Miscellaneous Products of the Mollusca. In China the 

 shells of a great number of molluscs, inhabitants of the 

 sea, river, or land, are pulverized and washed with great 

 care to prepare an absorbent powder, employed in erup- 

 tions and for toilet use. The valves of some Unios, of 

 Area granosa, and oyster shells are also calcined and pul- 

 verized to prepare medicines prescribed in fevers, apoplexy, 

 and haemorrhages. 



Opercula. Many species of gasteropods develop an 

 operculum or lid on a particular lobe of the foot. It may 

 be composed either of layers of horn or of dense shelly 

 substance, the principal office of which is to close the mouth 

 of the shell when the animal retires within it. The 

 operculum always exhibits more or less of a spiral deve- 

 lopment. In some cases the spirals are numerous and 

 nearly concentric ; in others, and these the most common, 

 the new matter is added principally on one side, and the 



