Biomphalaria haydeni Pierce, 1993 † (basis of record)
Biomphalaria spira Pierce, 2001 † (original description)
Cincinnatia bowmanana Pierce, 2001 † (original description)
Coelostemma (Coelostemma) dawsonae Pierce, 2001 † represented as Coelostemma dawsonae Pierce, 2001 † (original description)
Deroceras mahiz Pierce, 1992 † (basis of record)
Deroceras securis Pierce, 1992 † (basis of record)
Fluminicola calderensis Pierce, 2001 † (original description)
Gastrocopta akokala Pierce, 2001 † (original description)
Gastrocopta kintlana Pierce, 2001 † (original description)
Gastrocopta minuscula Pierce, 1992 † (basis of record)
Gyraulus scabiosus (G. D. Hanna, 1922) † (basis of record)
Haplotrema simplex (L. S. Russell, 1955) † (basis of record)
Helisoma triangulata Pierce, 2001 † accepted as Helisoma triangulatum Pierce, 2001 † (original description)
Holospira (Haplocion) beardi Pierce, 2001 † accepted as Haplocion beardi (Pierce, 2001) † (original description)
Holospira (Haplocion) tabrumi Pierce, 2001 † accepted as Haplocion tabrumi (Pierce, 2001) † (original description)
Lucidella (Poeniella) columbiana Pierce, 2001 † represented as Lucidella columbiana Pierce, 2001 † (original description)
Lucidella (Poeniella) salishora Pierce, 2001 † represented as Lucidella salishora Pierce, 2001 † (original description)
Lymnaea bowmanana Pierce, 2001 † accepted as Stagnicola bowmananus (Pierce, 2001) † (original description)
Lymnaea lacerta Pierce, 2001 † accepted as Galba lacerta (Pierce, 2001) † (original description)
Menetus hilli Pierce, 2001 † (original description)
Menetus textus Pierce, 2001 † (original description)
Nesovitrea (Perpolita) pulchra Pierce, 1992 † accepted as Perpolita pulchra (Pierce, 1992) † (basis of record)
Omalonyx antiqua (L. S. Russell, 1955) † (basis of record)
Omalonyx cocleare Pierce, 2001 † (original description)
Oreohelix dawsonae Pierce, 2001 † (original description)
Oxyloma kintlana Pierce, 2001 † accepted as Oxyloma kintlanum Pierce, 2001 † (original description)
Planorbella fordensis Pierce, 2001 † (original description)
Planorbella valens (A. B. Leonard & Franzen, 1944) † (basis of record)
Polygyroidea montivaga Pierce, 1992 † (basis of record)
Praticolella lucifera Pierce, 2001 † (original description)
Pupoides (Ischnopupoides) costatus Pierce, 2001 † represented as Pupoides costatus Pierce, 2001 † (original description)
Pupoides (Ischnopupoides) tephrodes B. Roth, 1986 † represented as Pupoides tephrodes B. Roth, 1986 † (basis of record)
Radiocentrum kintlana Pierce, 2001 † (original description)
Skinnerelix rothi Pierce, 2001 † (original description)
Sphaerium (Musculium) discus Pierce, 2001 † represented as Sphaerium discus Pierce, 2001 † (original description)
Sphaerium progrediens L. S. Russell, 1952 † (basis of record)
Succinea papillispira C. A. White, 1876 † (status source)
Tozerpina buttsi (L. S. Russell, 1955) † (basis of record)
Tozerpina buttsi parva Pierce, 2001 † (original description)
Tozerpina lentis Pierce, 2001 † (original description)
Tozerpina rutherfordi (L. S. Russell, 1929) † (basis of record)
Tryonia ellipsostoma (Pilsbry, 1934) † (basis of record)
Tryonia hibbardi (A. B. Leonard & Franzen, 1944) † (basis of record)
Tryonia russelli Pierce, 2001 † (original description)
Vallonia kootenayorum Pierce, 2001 † (original description)
Valvata procera spatiosa Pierce, 2001 † (original description)
Vertigo consteniusi Pierce, 2001 † (original description)
Vertigo doliara Pierce, 2001 † (original description)
Vertigo micra Pierce, 2001 † (original description)
Waldemaria monticula Pierce, 1989 † (basis of record)
Xerarionta constenii Pierce, 2001 † (original description)