Suborder VERRUCOMORPHA, Pilsbry 1916

Verrucomorpha Pilsbry, 1916: 14. - Newman et al. 1969: 281. - Newman and Ross 1971: 135. - Newman 1987: 8. - 1996: 501. - Buckeridge 1994: 89. - Young 1998: 74.

Diagnosis.

Shell asymmetrical with four plates (carina, rostrum, tergum and scutum), base membranous or calcareous.