FRONT-GILLED GROUP 



3353 



The cowry, or, more properly, kauri shells {Cyprczid<z~) , are so well known 

 that a description is scarcely necessary. They are all formed much after the 

 same pattern, and are almost always coated with a brilliant enamel, caused by the 

 lateral lobes of the mantle being reflexed upon the shell. In the young the shells 

 exhibit a short spire, which in the course of growth becomes entirely or almost 

 concealed. Many of the shells are exceedingly beautiful, and some of the animals 

 are even more brilliantly colored. The cowries have no operculum, but have a 

 large foot, and can retract their bodies entirely within the shell, notwithstanding the 

 narrowness of the aperture. The shells, as is well known, are sold as ornaments, 

 and some of the rarer kinds are greatly prized by collectors. A small yellow 

 species, the money cowry {Cyprcea monetd), abundant in some parts of the Indian 



FIG-SHELL (Pirula ventricosd), FROM ABOVE AND BENEATH. 

 (Natural size.) 



and Pacific Oceans, is used as coin in India and among the negroes of certain 

 parts of Africa. The orange cowry (C. aurora), one of the finest of the group, 

 used to be worn by the chiefs in the Friendly islands. The cowries, of which 

 nearly two hundred species are known, are found most abundantly in tropical 

 regions, but a few stragglers occur in temperate seas. Only one small and ridged 

 species (C. europ&a) is found on the British coasts, and about a hundred fossil 

 forms, chiefly Tertiary, are known. The genus Omda is allied to Cyprtza as 

 regards the general conformation of the animal, but has a somewhat different 

 radula and shell. It contains several subgenera, the most important being Radius, 

 Ultimus, and Calpumus. Radius volva is perhaps the most remarkable of all the 

 species. Many of them live parasitically upon sea fans, the shells assuming the 



