GYPRJEIDJE. 159 



I. Cypraea. 



Subgenus Cypraea Front of columella broad, deeply 



impressed ; shell mostly smooth. 

 Subgenus Aricia Front of columella flat or nearly so, back 



of shell smooth. 

 Subgenus Naria Front of columella narrow, dilated into a 



sharp-toothed ridge ; shell smooth. 



II. Luponia Shell like cowry, but front end of the columellar 

 lip crossed by several irregular ridges without any dis- 

 tinct marginal one ; internally narrow, flat, shell pear- 

 shaped, smooth or ribbed. 



III. Cypraeovula Like cowry, but front end of columella 

 covered with regular cross-ribs like rest of base, inter- 

 nally produced into an acute toothed ridge, shell pear- 

 shaped and ribbed. 

 IY. Trivia Like Cypraeovula, but front of columella internally 



concave, ribbed, shell subglobular, cross-ribbed. 

 (Erato and Ovulum are now excluded from this family.) 



The Messrs. Adams modified these groups and added others, 

 as follows : 



Cypraea, representing the cylindrical forms, with Naria as a 



subgenus. 



Aricia, shells with flattened base. 

 Luponia ; Cypraeovula ; Trivia, with Pustularia as a subgenus 



for pustulate forms ; and Epona. 



Under this arrangement, C. carneola would be entitled to a 

 place in Aricia as well as in Cypraea. 



Sowerby in " Thesaurus Conchyliorum " makes two divisions : 



A. Cypraea, proper. Columella ending in a lobe and plait. 



B. Cypraea, subgenus Trivia. Columella without distinct lobe 



or plait. 



He attempts to arrange the species in the order of their 

 nearest allies. 



Dr. Troschel named two families : Cypraeacea, Triviacea, 

 basing his subdivisions upon differences in dentition; but as 

 these differences do not agree with those of the general charac- 

 ters of the shell, they need not be further considered. The first 



