22 



58 Unio Obscurus, p. 194 



59 Cumberlandianus, p. 



195 

 60 Miiklfeldianus, p. 196 



PLATE XXIII. 



1 Unio Cresserus, p. 196 



2 Glaber, p. 196 



3 Simus, p. 197 



4 Menkianus, p. 191 



5 Venustus, p. 192 



6 Hydianus, p. 192 



7 Pulcher, p. 193 



8 Medellinus, p. 193 



9 Notatus, p. 193 



10 Dorfeuillianus, p. 179 



11 Graniferus, p. 180 



12 Carbonarius,* p. 184 



13 Pumilis, p. 185 



14 Barnesianus, p. 185 



15 Solidus, p. 186 



16 Luteolus, p. 192 



17 Productus, p. 205 



18 Masoni, p. 201 



19 Involutus of Benson, 



APP. 



20 Ascia of Benson, app. 



21 Unio Granosus, p. 182 



22 Conradicus, p. 176 



23 Dromas, p. 181 



24 Troostensis, p. 186 



25 Shepardianus, p. 203 



26 Taitianus, p. 186 



27 Kirklandianus, p. 203 



28 Griffithianus, p. 199 



29 Personatus, p. 202 



30 Rotundatus, p. 201 



31 Nashvillianus, p. 193 



32 Fulvus, p. 200 



33 Globosus, p. 189 



34 Confertus, p. 200 



35 Pictus, p. 191 



— — Divaricatus, p. 197 



Modioliformis, p. 209 



Hildrethianus, p. 196 



Swananoensis, p. 211 



Scobina, Benson, 



APP. 



Radula, Benson, app. 



Velaris, Benson, app. 



43 Corbis, Benson, app. 



44 - - (Alasmodonta) Radia- 



36 



37 

 38 

 39 

 40 



41 



42 



45 

 46 



tus, p. 212 



— Stramineus, p. 209 



— Arcus, p. 207 



* Repeated by mistake. Is acknowledged by Lea to be an aged 

 Pliciferus. 



