98 



Cincinnati Society of Natural History. 



CLASS ACEPHALA. 

 Order Branchifera. 

 family unionid/e. 



GENUS SYMPHYNOTA, (Fer.) 



(Hinge line extended into a wing.) 

 " i . Symphynota alata, Say. 



L. 6 or more, VV. 5 from tip of wing. Nacre purple. 



2. Symphynota pressa, Lea. 



L, 3, H. 1 3^, compressa, rayed with green. 



3. Symphynota gracilis, Barn. 4. 



L. 5^ and over, H. 3^ and over. In old specimens yellow 

 color. 



4. Symphynota laevissima, Lea. 



L. 6 or less, H. 4^. In old specimens, dark, finely rayed, nacre 

 pink. Wing more extended than in No. 3. 



Genus Unio. 



5. Unio abrupta (orbiculata), Say. 



L. 3, H. 2 and over. Dark yellow, two or more dark rays. 

 Female (?) shorter and more abrupt than male (J). 



6. Unio ^Esopa, Green. 



L. 2^, H. 2. Light straw color; a row of nodules down 

 middle of shell. 



7. Unio anodontoides, Lea. 



L. 33^ and over, H. subcylindrical, yellow, female rayed 



with green stripes. 



8. Unio circula, Lea. 



L. 2]/ 2 and less, H. 2^ and less. Dark color. 



9. Unio clava, Lam. 



L. 2^, H. 1^. Very oblique, yellow, rayed with dark green. 



10. Unio coccinea, Hdd. 



L. 2^ and over, H. 2 and over. Nacre rich salmon color. 



11. Unio cooperiana, Lea. 



L. 3, H. 3. Blunt tubercles on lines of growth, which stand 

 out in ridges. 



12. Unio cornuta, Barn. 



L. 2, H. 2. One row of two or more blunt tubercles down 

 each side of the shell. 



