FAMILY 3. NERITACEA. 139 
Neritz were distinguished long before by Lister in the plates of his 
‘Synopsis Conchyliorum ;’ and they were distributed by this excellent 
draughtsman in the order subsequently adopted by Lamarck ; the Neri- 
tine, the Nerite and the Natice being respectively associated by them- 
selves. We have sufficiently explained in our observations on the pre- 
ceding genus, why the first two of these divisions should remain sepa- 
rated; the Natice are still more distinct; in treating of them we shall 
be enabled to show that they differ materially, approaching rather in 
their organization to the Sigareti. 
The shell of Nerita may be described as being solid, semiglobose, flat- 
tish underneath, and either smooth or ribbed on the outside. The spire 
is short, there is no umbilicus, and the aperture is semicircular, and 
generally crenated within ; the columella is wide, septiform, and for the 
most part denticulated; the lip is either simple or crenulated. The 
operculum is testaceous, and furnished, like that of the Neritine, with a 
sharp lateral appendage. 
The Neritz are all marine, and their shells exhibit a great diversity of 
colour. 
Examples. 
Pl. CCII. Fig. 1 and 2. 
Nerita petoronta, Linneus, Syst. Nat., p. 778. Chemnitz, Conch., 
vol. v. pl. 192. f. 1977 to1984. Encyclopédie Méthodique, pl. 454. 
ity De le 
Peloronta 2? Oken. 
Pl. CCI. Fig. 3. 
Nerita cHLorostoma, Lamarck, Anim. sans vert., new edit., vol. vill. 
p. 603. Encyclopédie Méthodique, pl. 454. f. 4. a, b. 
Pl. CCIL. Fig. 4. 
Nerira ornata, Sowerby, Genera of Shells, No. 10. 
Pl. CCII. Fig. 5. (fossil.) 
Nerira Granuata, Defrance. Sowerby, Genera of Shells, No. 10. 
Neritopsis (?) 
2 
