COLUMBELLA. 113 



The next section, included in the family Auriculacea, Bh. con- 

 tains the genera Auricula, Chilina, Carychium, Marinula, 

 Scarabseus, and Partula. Fig. 297 to 302. 



The third section contains the following genera of land shells 

 with opercula. 



1. Cyclostoma. Aperture round; operculum spiral. Fig. 



303, 304. 



2. Nematura. Last whorl contracted; operculum spiral, 



Fig. 305. 



3. Helicina. Aperture semilunar or angulated ; operculum 

 concentric. Fig. 306, 307. 



4. Pupina. Shell polished; operculum concentric; aperture 

 round. Fig. 



5. Strophostoma. Aperture turned up towards the spire, 

 like Anostoma, but said to have an operculum. Only 

 known fossil. Fig. 97. 



COLUMBELLA. Auct. (Columba, a dove.) Fam. Columel- 

 lata, Lam. — Descr. Thick, oval, or angular ; with short spire, 

 and long narrow aperture, contracted in the centre, and termi- 

 nating in a short canal ; outer lip thickened and dentated ; 

 inner lip irregularly crenated. Epidermis thin, brown. Oper- 

 culum very small, horny. — Obs. Those species of Mitra, which 

 resemble Columbella in shape, may easily be distinguished by the 

 plaits on the columella. The Columbelloe 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 Cerithmm; Ni- 

 tidella, consisting of the smooth species ; Conidea, consisting of 

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

 has been removed from this family, 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 com- 

 pleting the ' ' circle" of the last mentioned family, which other- 

 wise would not have reached the required number of five. Medi- 



