Studies in <i>Canarium urceus</i> (Linné, 1758) Part 2: <i>Strombus anatellus</i> Duclos, 1844, <i>Strombus crassilabrum</i> Anton, 1839, <i>Strombus incisus</i> Wood, 1828 and <i>Strombus ustulatus</i> form <i>laevis</i> Dodge, 1946 (Neostromboidae: Strombidae)