Call — The Unionidoe, of Arkansas. 66 



LIST OF PLATES. 



Plate I. Unio clavus Lamarck. 



II. Unio crassidens Lamarck. 



III. Unio luteolus Lamarck. 



IV. Uaio obliquus Lamarck. 



V. Uoio purpuratus Lamarck. Male and female 

 VI. Unio purpuratus Lamarck. Female. 

 VII. Unio rectus Lamarck. 

 VIII. Unio retusus Lamarck. 

 IX. Unio rotundatus Lamarck. 

 X. Unio metanevrus Raflnesque. 

 XI. Unio cvlindricus Say. 

 XII. Unio schoolcraftii Lea. 



XIII. Unio schoolcraftii Lea. Varieties. 



XIV. Unio schoolcraftii Lea. Figures 1-4. 

 Unio pustulosus Lea. Figures 5-6. 



XV. Unio dorfeuillianus Lea. Figures 1-2. 

 Unio refulgeus Lea. Figures 3-4. 

 XVI. Margaritana complanata Barnes. 

 XVII. Unio breviculus Call. From U. S. Nat. Museum. 

 XVIII. Unio ozarkensis Call. From U. S. Nat. Museum 

 XIX. Unio sayii Ward. Figures 1-2. 



Unio sayanus Conrad. Figures 3-6. 

 XX. Unio excultus Conrad. Figures 1-3. 

 Unio tetralasmus Say. Figures 4-6. 

 XXI. Unio ligamentinus Lamarck. 



