Hundreds of field trips over a period of more than 40 years, to a broad swath of Middle Claiborne fossil localities in the Gulf Coast, resulted in the discovery of many new taxa. This study discusses and describes many of the better-preserved taxa found. A new family Surculitidae is proposed; the following new genera and subgenera are proposed: Trochilepas, Siphonalia (Katherinalia), Eocymia, Surculamella, and Ossacythara. The following 108 new species and subspecies are proposed: Trochilepas harasewychia, Acmaea claibornica, Clypidina (Clypidina) fragilis, Fissurellidea eogentis, Coanollonia eocaenica, Bayania elegans, Bayania ? funicula, Dirocerithium parvabrazensis, Elimia texana, Alaba laevae, Nanggulania americana, Capulus coqueremons, Lippistes eocaenica, Priscoficus lenis, Neverita (Neverita) elongata, Polinices symondsi, Anticlimax traceyi, Tornus beadata, Cochliolepis problematica, Teinostoma (Megatyloma) gosportensis, Meioceras smithvillensis, Onustus coqueremons, Macromphalina parvicostata, Macromphalina parviexempla, Melanella carinata, Phalium (Semicassis ?) wechesensis, Sconsia wrigleyi, Ranella murus, Ptychosalpinx texana, Siphonalia (Katherinalia) neptuniformis, Siphonalia (Katherinalia) multiformis, Papillina dumosa wechesensis, Latirus brevilenis, Heligmotoma nacogdochensis, Fusinus pseudopagoda, Conradconfusus claibornensis, Falsifusus nacogdochensis, Falsifusus spiralis, Falsifusus sublimis, Cantharus houstonensis, Cantharus uitta, Amphissa alabamensis, Levifusus gracilis, Levifusus irrasus lineatus, Dorsanum elongatum, Paleofusus wechesensis, Searlesia duplicata, Pterynotus robustus, Hexaplex tejasensis, Hexaplex nudus, Phyllonotus multilaminus, Murexsul iuvenilis, Murexiella squamosa, Eocymia claibornica, Ficulomorpha eocaenica, Harpa atascosita, Volutocorbis claibornica, Volutocorbis quadrataformis, Scaphella burlesonensis, Exilia wechesensis, Exilia kantori, Anbullina minor, Anbullina ? laevicutis, Ancillus wechesensis, Surculites montgomeriensis, Surculamella parvabrazensis, Hastula (Bulbihastula) iuga, Gemmula complanata, Hesperiturris acuticosta, Trypanotopsis lisbonensis, Microsurcula praeintacta, Microsurcula stromboida, Protosurcula obesus, Cordiera crassisculpta, Scobinella (Moniliopsis) elegansa, Awateria meta, Microdrillia faba, Microdrillia elongata, Pleurofusia imminutia, Cochlespira nuda, Austrocarina nitidus, Leptosurcula nodofenestra, Leptosurcula alabamensis, Eoclathurella coqueremons, Eoclathurella tenuis, Eoclathurella ? elegantissima, Ossacythara wechesensis, Phandella gosportensis, Eodaphne brazosensis, Caveola elongata, Unitas wechesensis, Unitas gosportensis, Microcancilla parvastavensis, Coptostoma nacogdochensis, Architectonica fungina teres, Architectonica (Granosolarium) umbilicrassa, Pseudotorinia ? bieleri, Pseudomalaxis gosportensis, Turbonilla parallela, Turbonilla pseudoeulimella, Parthenina longiformis, Puposyrnola palus, Eulimella parvabrazensis, Eulimella texana, Scaphander punctatus, Rhizorus spinosus, Atys tumidus, and Physa aequua. Two new species are left in open nomenclature: Eunaticina ? sp. and Sigatica sp. The following poorly known taxa are also discussed and new combinations assigned when necessary: Galeodea dubia (Aldrich, 1885), Levifusus ? harrisi Grabau, 1903 (neotype here designated), Echinofulgur cf. explicatus (Conrad, 1833b) (neotype here designated), Murex fusates G. D. Harris, 1895a, Tropidoturris dipta (G. D. Harris, 1937), Tropidoturris pinaculina (de Gregorio, 1890) (neotype here designated), and Pleurofusia longirostropis de Gregorio, 1890 (neotype here designated). With an approximate 12% increase in the number of new gastropod species described from the middle Claibornian Eocene, the total number is now more than 1,000 species, indicating a more diverse biota than previously understood, especially within the Weches and Cane River formations.