This Index has been compiled to assist the numerous visitors, who wish to examine and determine specimens of shells, in finding, without trouble or loss of time, the Cases in which the genera are placed. Subgeneric terms are omitted, as they do not fall within the scope of this “Guide.” Acanthina, 75 Achatina, 130–131 Achatinella, 134, 135 Acmæa, 4 Actæon, 94 Ætheria, 178 Amphibola, 98 Amphiperas, 35 Ampullaria, 25, 26 Amussium, 159 Anatina, 203 Ancylus, 99 Anodonta, 166, 167 Anomia, 137 Anostoma, 128 Aplacophora, 3 Aplustrum, 96 Aplysia = Tethys, 96 Aporrhais, 49 Arca, 139 Arctica, 162 Argonauta, 205, 206 Arion, 107 Aspergillum (= Brechites), 204 Astarte, 161 Atlanta, 94 Auriculidæ, 97, 98 Avicula = Pteria, 145 Batissa, 165 Brechites, 204 Bryopa, 204 Buccinum, 65 Buliminus, 128 Bulimulus, 122 Bulimus = Strophocheilus, 120 Bullidæ, 95 Calyptræidæ, 31, 32 Cancellaria, 77 Capulus, 31 Cardita, 160 Cardium, 192–194 Carinaria, 94 Cassis, 55–56 Cerion, 129 Cerithiidæ, 42–44 Chætoderma, 3 Chama, 196 Chitonidæ, 1–3 Chrysodomus, 64 Circe, 187 Clausilia, 129–130 Clavagella = Bryopa, 204 Columbella, 69 Conus, 89–94 Coralliophila, 76 Corbicula, 164 Corbis, 163 Corbula, 198 Crassatella, 161 Crenatula, 147 Crenella, 145 Cucullæa, 140 Cuma, 75 Cuspidaria, 204 Cyclophoridæ, 23, 25 Cyclostomatidæ = Pomatiidæ, 28, 29 Cylindrella, 127 Cypræa, 32–35 Cyprina = Arctica, 162 Cyrena, 164 Cythera = Meretrix, 185 Delphinula, 12 Dentalium, 136 Despoena, 22 Diplodonta, 163 Dolium, 56, 57 Donax, 182 Dosinia, 188 Dreissensia, 179 Eburna, 67 Emarginula, 7 Ennea, 103 Eucalodium, 129 Eulima, 46 Fasciolaria, 59 Ficula = Pirula, 57 Fissurella, 8 Fulgur, 61 Fusus, 57, 58 Gadinia, 99 Galatea, 165 Galeomma, 163 Gastrochæna, 201 Gena, 11 Glandina = Oleacina, 102 Glauconome, 192 Glycymeris, 141 Haliotis, 9–11 Haminea, 95 Harpa, 84 Helicarion, 104 Helicidæ, 107–121 Helicina, 21 Hemifusus, 61 Heteropoda, 24 Hinnites, 159 Hydatina, 96 Ianthina, 38 Isocardia, 162 Isognomon = Melina, 147 Kellia, 163 Latiaxis, 74 Latirus, 59 Leda = Nuculana, 137 Lepeta, 4 Lepton, 163 Lima, 156 Limax, 106 Limnæidæ, 99–102 Limopsis, 141 Lithodomus, 144 Littorina, 27 Loligo, 207 Lotorium, 53, 54 Lucinidæ, 162, 163 Lutraria, 199 Lyonsia, 203 Mactridæ, 183–185 Magilus, 77 Malletia, 137 Malleus, 146 Marginella, 83, 84 Melaniidæ, 38–41 Meleagrina, 146 Melina, 147 Melongena, 61 Meretrix, 185 Mesodesma, 182 Mitridæ, 61–64 Modiola, 143, 144 Modiolarca, 145 Modiolaria, 145 Monoceros = Acanthina, 75 Montacuta, 163 Murex, 70–73 Mutela, 177 Mya, 198 Myadora, 203 Mycetopus, 176 Myochama, 203 Mytilus, 142, 143 Nassa, 67, 68 Naticidæ, 36, 37 Nautilus, 208 Navicella = Septaria, 20, 21