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CONCHOLOGY. 
Cerithium palustre. 
C. telescopium. 
C. nodulosum. 
C. obeliscum. 
aluco. 
. giganteum. 
. sulcatum. 
ebeninum. 
vulgatum. 
. granulatum. 
. echinatum. 
subulatum. 
zonale. 
tortulosum. 
morus. 
erythreonense. 
. radula. 
. decollatum. 
semigranosum. 
lineatum. 
CRORES A= eRe honor eae heohone © 
Cerithium fasciatum. 
C. muricatum. 
C. crassum. 
C. obtusum. 
C. asperum. 
C. vertagum. 
C. literatums> 
. heteroclites. 
. semiferrugineum. 
C. tuberculatum. 
ocellatum. 
atratum. 
eburneum. 
lima. 
C 
C 
C 
C 
zonatum. 
rugosum. 
mitriforme. 
C 
C. 
C. 
C. 
C. 
C. punctatum. 
C. perversum. 
C. petrosum. 
C. Emersonii.* 
C. Nigrocinctum.* 
C,. Greenii.* 
C. exasperatum.* 
C. dislocatum.* 
2. Genus Pleurotoma. Pl. XI. 
Animal. 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 branchiz. 
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. 
