1/4 TESTACEOUS MOLLUSCA. 



Division A. — Unio Proper. 



With a cardinal and lateral tooth. 



Section A. — Symphonote. 1 



U. Inflatus. Lea. — Symphonota I. Lea's Unio. vol. 1. 

 p. 109. t. 14. Triangular ovate, inequilateral, ventricose, very 

 thin, elevated into a broad high wing posteriorly, a small one an- 

 teriorly, both connate ; cardinal tooth single in both valves, lateral 

 teeth bladed towards their termination ; beaks slightly prominent ; 

 ligament concealed ; nacre purple, cuticle brown with obsolete rays. 

 2f..4j. — R. Alabama. 



U. Alatus. Say. — Lam. 28. — Swain. Ex. C. t. 7. — Lea on 

 U. I. p. 62. — Mya A. IV.S.f. 3. Triangular ovate, transversely 

 wrinkled, rather compressed, moderately thick, elevated into a high 

 wing and connate over the ligament ; beaks scarcely prominent, 

 cardinal tooth double in both valves, lateral tooth double in the 

 left valve only and slightly curved : ligament concealed, nacre 

 purple. 4 t 7 q . . 6 T 9 y . — Is. America.* 



U. Llevissimus. Desh. in Lam. 6. p. 558. — Symphonota L. 

 Lea, on U. 1. p. 58. t. 13. f. 23. Subtriangular-ovate, inequi- 

 lateral, subventricose, finely wrinkled transversely, shining, thin, 

 with two not very high wings, the anterior the larger, both con- 

 nate ; beaks scarcely prominent ; ligament concealed ; cuticle 

 purplish brown, nacre purple and irridescent : cardinal and lateral 

 teeth forming a curved line. 2| . . 4 J. — Ohio. 



U. Gracilis. Barnes in Sil. Am. J. 6. — Symph. G. Lea. — 

 U. Planus. Barnes. — U. Fragilis. Swain. Z. II. vol. 3. Sub- 

 triangular-ovate, inequilateral, transversely wrinkled, rather com- 

 pressed, thin, anterior dorsal edge connate, wing but little elevated, 

 beaks scarcely prominent ; ligament concealed ; nacre pearly, 

 violet-purple, irridescent, cuticle yellowish green. 2 J . . 3-^. — Ohio. 



U. Compressus. Lea. — Sym. C. Lea on U. 1. p. 64. t. 12. 

 /. 22. Transverse, much compressed, elliptical, inequilateral, 

 thin, posteriorly rounded, beaks slightly elevated, not decorticated, 

 crowned with small double concentric elevations, tips almost white ; 

 anterior dorsal edge rather elevated and angulated at its extremity : 

 cuticle olive green with broad rays all over the disc, nacre pale 

 salmon becoming bluish near the margin ; cardinal tooth promi- 

 nent, lateral small. 2| . . 1 ^. — Ohio. 



1 To this division belongs the genus Hyria of Lamarck. 



2 Add likewise the Lymnadia Gigas of Swainson. 



