﻿CONTENTS 



Introduction iii 



Catalogue of the Naiades i 



Family UNIONID^, i 



Subfamily Unioninse i 



Heterogen.^ I 



Genus Truncilla 2 



MiCROMYA 32 



Lampsilis 35 



Friersonia 200 



pseudospatha 202 



Hyriopsis 207 



Chamberlainia 219 



SiMPSONIA 221 



Cristaria 223 



Lepidodesma 237 



Pilsbryoconcha 239 



Medionidus 245 



Nephronaias 253 



Glebui.a 286 



Obovarta 289 



Plagiola 302 



DiGEN.-E 317 



Tritogonia 317 



Hemieastena 323 



Mesogen.^ 326 



Cyprogenia ^26 



Obiiouaria 329 



PTYCHOGEN.li ^^2 



PTYCHOBRANCHUS ^T^2 



