452 NEW GENUS AND SOME NEW SPECIES 



6. Symphynota Gracilis. 



Testa sub-triangulari-ovata, incequilaterali, Iransversim rugosd, sub- 

 compressd; vctlvulis tenuibus fragilibusque ; mar gine posteriori dorsali 

 sub-alata, c'onnataque; dente cardinali invalvula dextra elevato, recur v o ; 

 natibus sub-prominulis ; ligamento celato ; margarita violaceo-purpurea 

 et iridescente. 



Shell sub-triangular-ovate, inequilateral, transversely wrinkled, rather 

 compressed; valves thin and fragile; posterior dorsal margin connate, 

 wing but little elevated ; cardinal tooth of right valve elevated, recurved ; 

 beaks scarcely prominent; ligament concealed; nacre pearly, violet- 

 purple, and iridescent. 



Hab C Ohio. T. G. Lea. 



I Wisconsan. Mr Schoolcraft. 

 . My Cabinet. 

 Cabinet of Mr Barnes. 

 Cabinet of Prof. Vanuxem. 

 Cabinet of P. H. Nicklin. 

 Cabinet of Mr Swainson. 

 Cabinet of the New York Lyceum. 

 Cabinet of the Academy of Natural Sciences. 

 Unio gracilis. Barnes. Silliman's Amer. Journ. Vol. VI. 

 p. 174. 



Unio fret gilis. Swainson*. 

 Unio planus. Barnes. 

 Diam. 1 — 1-2, Length 2-2 — 2*5 inches. 



Breadth 3-1 — 4-1 inchesf. 



Shell sub-triangular-ovate, inequilateral, transversely wrink- 

 led, rather compressed ; substance of the shell thin ; valves ele- 

 vated into a small wing over the ligament and connate ; beaks 

 slightly prominent, pointed, having two or three minute ele- 

 vations ; ligament concealed in the wing ; epidermis yellow- 



* I have retained the specific name of Mr Barnes in preference to that of Mr 

 Swainson in the right of priority. Mr B. published in January 1C23. Mr S.'s 

 dedication of 3d vol. of his Zool. Illus., in which the fragilis is described, is dated 

 Oct. 1823. 



t Sec Barnes's description. 



