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CONCHOLOGF. 



Cerithium palustre. 



C. lelescopium. 



C. nodulosum. 



C. obeliscum. 



C. aluco. 



C giganteum. 



C. sulcatum. 



C. ebeninum. 



C. vulgatum. 



C. gran u latum. 



C. echinatura. 



C. subulatum. 



C. zonale. 



C. tortulosum. 



C morus. 



C. erythraeonense. 



C. radula. 



C. decollatum. 



C. semigranosum. 



C lineatum. 



C. exasperatum.^ 

 C. dislocatum.* 



C. Greenii.* 



Cerithium fasciatum. 



C. muricatum. 



C. crassum. 



C obtusum. 



C. asperum. 



C. vertagum. 



C. literatum. 



C. heteroclites. 



C. semiferrugineum. 



C. tuberculatum. 



C. ocellatum. 



C. atratum. 



C. eburneum. 



C. lima. 



C. zonatum. 



C. rugosum. 



C. mitriforme. 



C. punctatum. 



C. perversum. 



C. petrosum. 



C. Emersonii.* 

 C. Nigrocinctum.* 



2. Genus Pleurotoma. PI. XI. 



Jlnimal. Body oval, spiral above, enveloped in a mantle of 

 which the right edge is furnished with lobes ; foot oval and some- 

 what short ; eyes situated at the external base of long, conical, 

 retractile tentacula ; mouth having a long extensible proboscis 

 armed with hooked teeth ; organs of respiration formed by two 

 unequal branchiae. 



Shell. Fusiform, a little wrinkled, with a turriculated spire ; 

 a small oval aperture, terminated by a straight canal more or less 

 long, with the right edge trenchant ; a horny operculum. Dis- 

 tinguished from the Cerithium by having a notch in the margin. 

 Twenty-nine living species. Thirty fossil. 



