CLASSIFICATION. XV 
#7. Trocuus: Aperture contracted, nearly rectangular. 
28. Turso: Aperture contracted, and orbicular. 
29. Hextix: Aperture contracted, lunate on the inner side. 
30. Nerita: Aperture contracted, and semiorbicular. 
31. Haxioris: Shell with a row of orifices along the surface. 
2. Without a regular Spire. 
82. Patevta: Shell conic, the aperture widened like a basin. 
33. Denratium: Shell slender, subulate, open at both ends. 
34. Serputa: Shell tubular, generally serpentine, adhering 
to other bodies. 
35. Terepo: Shell thin, penetrating wood. 
386. Sapeiia: Shell composed of agglutinated grains of sand. 
