Call — The Unionidce of Arkansas. 66 



LIST OF PLATES. 



Pi>ATE I. Unio clavus Lamarck. 



II. Unio crassidens Lamarck. 



III. Uoio luteolus Lamarck. 



IV. Unio obliquus Lamarck. 



V. Unio 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 Rafinesque. 

 XI. Unio cylindricus 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 dorfeuilliaous Lea. Figures 1-2. 

 Unio refulgens 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. 



