Anculosa Say, 1821 accepted as Leptoxis Rafinesque, 1819 (original description)
Bulla fluviatilis Say, 1821 accepted as Planorbella trivolvis (Say, 1817) (original description)
Cyclostoma marginata Say, 1821 accepted as Pupoides albilabris (C. B. Adams, 1841) accepted as Pupoides nitidulus (L. Pfeiffer, 1839) (original description)
Helix appressa Say, 1821 accepted as Patera appressa (Say, 1821) (original description)
Helix chersina Say, 1821 accepted as Euconulus chersinus (Say, 1821) (original description)
Helix clausus Say, 1821 accepted as Mesodon clausus (Say, 1821) (original description)
Helix concava Say, 1821 accepted as Haplotrema concavum (Say, 1821) (original description)
Helix dealbata Say, 1821 accepted as Rabdotus dealbatus (Say, 1821) (original description)
Helix elevata Say, 1821 accepted as Mesodon elevatus (Say, 1821) (original description)
Helix gularis Say, 1821 accepted as Ventridens gularis (Say, 1821) (original description)
Helix inflecta Say, 1821 accepted as Inflectarius inflectus (Say, 1821) (original description)
Helix interna Say, 1821 accepted as Gastrodonta interna (Say, 1821) (original description)
Helix jejuna Say, 1821 accepted as Praticolella jejuna (Say, 1821) (original description)
Helix ligera Say, 1821 accepted as Ventridens ligera (Say, 1821) (original description)
Helix multilineata Say, 1821 accepted as Webbhelix multilineata (Say, 1821) (original description)
Helix obstricta Say, 1821 accepted as Xolotrema obstrictum (Say, 1821) (original description)
Helix palliata Say, 1821 accepted as Xolotrema notatum (Deshayes, 1830) (original description)
Helix profunda Say, 1821 accepted as Allogona profunda (Say, 1821) (original description)
Helix solitaria Say, 1821 accepted as Anguispira kochi (L. Pfeiffer, 1846) (original description)
Limnaea desidiosa Say, 1821 accepted as Catascopia elodes (Say, 1821) accepted as Ladislavella elodes (Say, 1821) (original description)
Lymnaeus columellus (Say, 1817) accepted as Pseudosuccinea columella (Say, 1817) (basis of record)
Lymnaeus elongatus Say, 1821 accepted as Catascopia elodes (Say, 1821) accepted as Ladislavella elodes (Say, 1821) (original description)
Lymneus appressus Say, 1821 accepted as Lymnaea stagnalis appressa (Say, 1821) accepted as Lymnaea appressa (Say, 1821) (original description)
Lymneus desidiosus Say, 1821 accepted as Ladislavella elodes (Say, 1821) (original description)
Lymneus elodes Say, 1821 accepted as Ladislavella elodes (Say, 1821) (original description)
Lymneus emarginatus Say, 1821 accepted as Ladislavella emarginata (Say, 1821) (original description)
Lymneus macrostomus Say, 1821 accepted as Pseudosuccinea columella (Say, 1817) (original description)
Lymneus reflexus Say, 1821 accepted as Catascopia elodes (Say, 1821) accepted as Ladislavella elodes (Say, 1821) (original description)
Melania armigera Say, 1821 accepted as Lithasia armigera (Say, 1821) (original description)
Melania canaliculata Say, 1821 accepted as Pleurocera canaliculata (Say, 1821) (original description)
Melania conica Say, 1821 accepted as Pleurocera canaliculata (Say, 1821) (original description)
Melania elevata Say, 1821 accepted as Pleurocera canaliculata (Say, 1821) (original description)
Melania praerosa Say, 1821 accepted as Leptoxis praerosa (Say, 1821) (original description)
Paludina integra Say, 1821 accepted as Cincinnatia integra (Say, 1821) (original description)
Paludina lustrica Say, 1821 (original description)
Paludina ponderosa Say, 1821 accepted as Campeloma crassulum Rafinesque, 1819 (original description)
Paludina porata Say, 1821 accepted as Amnicola limosus (Say, 1817) (original description)
Physa elongata Say, 1821 accepted as Sibirenauta elongata (Say, 1821) (original description)
Physa gyrina Say, 1821 accepted as Physella gyrina (Say, 1821) (original description)
Planorbis armigerus Say, 1821 accepted as Planorbula armigera (Say, 1821) (original description)
Planorbis campanulatus Say, 1821 accepted as Planorbella campanulata (Say, 1821) (original description)
Planorbis exacuous Say, 1821 accepted as Promenetus exacuous (Say, 1821) (original description)
Planorbis paralellus Say, 1821 accepted as Helicodiscus parallelus (Say, 1821) (original description)
Polygyra plicata Say, 1821 accepted as Daedalochila plicata (Say, 1821) (original description)
Pupa armifera Say, 1821 accepted as Gastrocopta armifera (Say, 1821) (original description)
Pupa rupicola Say, 1821 accepted as Gastrocopta rupicola (Say, 1821) (original description)