GASTEROPODA. 281 



The Cowrie shells are employed by Asiatic island- 

 ers to adorn their dress, to weight their fishing-nets, 

 and for barter. Specimens of them were found by Dr. 

 Layard in the ruins of Nimroud. The Money cowrie 

 (Cyprsea monetd) is used as money by the Africans : 

 hundreds of tons are imported to Liverpool and ex- 

 ported for barter.* 



The Harp-shells (Harpa) are recognisable by the 

 prominent ribs upon their surface, the last of which 

 forms the marginal border. These shells are very 

 beautiful ; the animal (Fig. 217.) is furnished with a 

 large foot, broad in front, and pointed posteriorly ; its 

 tentacles are provided with eyes situated near their 

 bases ; it has no operculum. 



The Helmet-shells (Cassis) are of an oval shape, 



FlG. 220. < ASSIS TUBKUOSA. 



* From a coarse comparison of the Cowrie shells to a pig's back, 

 they were vulgarly known to the Portuguese as Porcellane (Porcellus, 

 a little pig). When the beautiful ware known as china was first im- 

 ported, the resemblance of its glaze to the enamel of the Cowrie 

 shell caused it to be called "Porcelain." 



