COLUMELLATA. llT 



the plaits on the columella. The ColumbellEe . are marine, and 

 few fossil species are known. Fig. 430, C. Mercatoria. Swainson 

 has divided this genus into the following : Columbella, consisting 

 of C. Mercatoria, &c. ; Pusiostoma, consisting of the Strombiform 

 species ; Crassispira, which is most probably a Cerithium ; 

 Nitidella, consisting of the smooth species ; Conidea, consisting 

 of the more conical species ; another set of the more conical 

 species has been removed from this familyj and placed in that 

 of the " Coninse," but as they are separated by no essential 

 character, we suppose this has merely been done for the purpose 

 of completing the " circle" of the last mentioned family, which 

 otherwise would not have reached the required number of five. 

 Mediterranean, East and "West Indies, South America, Coast 

 of California, Gallapagos, &c. The Monograph of this genus in 

 the Author's Thesaurus Conchy liorum, contains 102 species. 

 Plates 36 to 40. Our figure, PL xx. fig. 430. 



COLUMELLA. The column formed by the inner sides of the 

 volutions of a spiral univalve. It is sometimes described as the 

 inner lip of the aperture, of which it forms a part ; but the term 

 would be more properly confined to that portion of the inner lip 

 which is seen below the body whorl, over which the remainder of 

 the lip is frequently spread. All the inner edge of the aperture, 

 including that part of it which covers the body whorl, is called 

 the columellar lip. In fig. 431, the anterior termination of the 

 columella is indicated by the letter c. The axis, is an imaginary 

 line drawn strictly through the centre of the whorls, whether 

 their inner edges form a solid column or not. 



COLUMELLAS LIP. The inner lip. See Columella. 



COLUMELLATA. Lam. A family of the order Trachelipoda, 

 Lam. containing the following genera : — 



1. MiTEA. Elongated ; aperture narrow ; strong folds on the 



columella; including Mitrella, Mitreola, Tiara, and Co- 

 nohelix. Fig. 431, 432. 



2. Marginella. Outer lip reflected; including VolutellUy 



Persicula, Gibherula, and Glabella. Fig. 437. 



