PART II. 



TROCHID.E. 



347 



NERITINA Lam. General shape of Nerita ; but the 

 outer lip is thin and smooth, the inner one rather 

 convex and crenated ; surface smooth. 



N. meleagris. Chem. 124. f. 1088. a i. 

 Clithon Montf. Leach. General shape of Neritina ; 

 but there is an obtuse lobe on the inner lip, the 

 outer is dilated at its origin, and the whorls are armed 

 with spires. 



C. corona. Chem. 124. f. 1083, 1084. 



Velotes Mont. Nearly orbicular; depressed; above 

 convex ; beneath flat ; spire nearly obsolete ; inner 

 lip toothed, as large as the aperture, which is semi- 

 circular. 



V. perversa. Sow. Man. f. 326. 



Pileolus Cookson. Shell above patelliform ; spire in- 

 ternal ; aperture beneath small, semilunar; outer lip 

 margined ; inner crenated. 



P. plicatus. Sow. Man. f. 332. 



Navicella Lam. Somewhat patelliform ; oval ; convex 

 above ; flat beneath ; aperture large ; inner lip nar- 

 row, thin, assuming the form of a plate across one 

 end of the under surface ; operculum shelly. * 

 N. elliptica. Sow. Man. f. 323. 



FAMILY TROCHID^. 



d 



Unites the NaticicUe to the Haliotidce, by Crepidula. 



