INDEX TO GENERA AND SUBGENERA. 



Numbers in heavy-face type indicate the page on which the genus or 

 subgenus first occurs as a valid name in the list. Page numbers in plain 

 type refer to synonyms. If a name occurs on two or more consecutive 

 pages, the number of the first page only is given. 



Abra, 75. 

 Abralia, 218. 

 Acanthinula, 211. 

 Acanthodoris, 173 

 Acella, 182. 

 Acirsa, 104. 

 Aclis, 93, 105. 

 Acmaea, 85. 

 Acrybia, 107. 

 Actaeon, 147. 

 Acteon, 99, 147. 

 Actinobolus, (51. 

 Adalaria, 173. 

 Adeorbis, 87, 120. 

 Admete, 140. 

 Aeolidia, 162. 

 Aeolis, 162. 

 Aequipecten, 28. 

 Agriolimax, 205. 

 Agriopoma, 69. 

 Alasmidonta, 26. 

 Alasmodonta, 23, 26. 

 Alderia, 161. 

 Alectrion, 110, 134. 

 Alexia, 178. 

 Aligena, 67. 

 Amauropsis, 107. 

 Amicula, 10. 

 Amnicola, 114. 

 Amphidesma, 75. 

 Amphisphyra, 149. 

 Amphitrite, 169. 

 AmpuUina, 107. 

 Anachis, 132. 



Anatina, 36. 

 Ancula, 176. 

 Ancylus, 192. 

 Anguispira, 207. 

 Angulus, 72. 

 Anodon, 23. 

 Anodonta, 24. 

 Anodontoides, 25. 

 Anomia, 31, 156. 

 Aphrodite, 69. 

 Aplexa, 180. 

 Aplysia, 153. 

 Aporema, 35. 

 Aporrhais, 128. 

 Area, 12, 13, 18. 

 Architectonica, 120. 

 Architeuthis, 219. 

 Arctoscala, 103. 

 Argina, 18. 

 Argonauta, 223. 

 Arion, 205. 

 Armiger, 191. 

 Arrhoges, 128. 

 Assiminea, 111. 

 Assiminia, 111. 

 Astarte, 42. 

 Astyris, 133. 

 Atalanta, 129. 

 Atlanta, 129, 155, 159. 

 Auricula, 178. 

 Avicula, 20. 

 Axinopsis, 65. 

 Axinulus, 64. 

 Axinus, 65. 



