CaU — TTie Unionidce of Arkansas. 65 



LIST OF PLATES. 



Platk I. Unio clavus Lamarck. 



II. Unio crassidens Lamarck. 



III. Uaio luteolas Lamarck. 



IV. Uaio obliquus Lamarck. 



V. Uuio parpuratas Lamarck. Male and female 

 VI. Unio purpuratus Lamarck. Female. 

 VII. Unio rectus Lamarck. 

 VIIL Unio retusus Lamarck. 

 IX. Unio rotundatus Lamarck. 

 X. Uuio metanevrua Raflnesqae. 

 XI. Unio cyliodricus Say. 

 XIL Unio schoolcraftii Lea. 



XIII. Unio schoolcraftii Lea. Varieties. 



XIV. Unio schoolcraftii Lea. Figures 1-4. 

 Unio pustulosus Lea. Figures 5-6. 



XV. Unio dorfeuillia-ius Lea. Figures 1-8. 

 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 4-5. 

 XXI. Unio ligamentinus Lamarck. 



