448 NEW GENUS AND SOME NEW SPECIES 



3. SyMPHYNOTA AlATA. 



Testa ovato-triangulari, transversim rugosA, sub-compressa ; valvulis 

 crassiusculis, earum marginibus dorsalibus alatis, ct super ligamento 

 connatis ; dente cardinali in valvulis ambabus duplici, laterali in sinis- 

 trA tantum duplici, subcurvato; ligamento sub alA celato ; natibus pro- 

 minulis ; margarita purpurea. 



Shell triangular-ovate, transversely wrinkled, rather compressed ; 

 valves 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. 



Hab. our western waters. 



Unio alatus. Say. Nicholson's Encyclopaedia (Am. Ed.) 

 Art. Am. Conch, pi. 4, fig. 2.* 



Unio alata. Lamarck. 



Unio alatus. Barnes. Silliman's Am. Journ. Vol. VI. 



Unio alata. Swainson. 

 Diam. 2, Length 4-7, Breadth, 6*9 inches.f 



Remarks. — In young specimens it appears disposed to be 

 connate anteriorly to the beaks also. The dorsal cicatrices 

 form quite a row across the cavity. 



4. Symphynota Compeanata. 



TestA ovato-triangulari, incequilaterali, transversim rugosA, compres- 

 sa; valvulis crassis; margine posteriori dor sail alata connataque ; dente 

 tmico cardinali in valvulA utrAque ; piano irregulari calloso sub liga- 

 mento ; natibus compressis, sub-prominulis ; ligamento celato ; marga- 

 ritA alba, iridescenli. 



Shell triangular-ovate, J inequilateral, transversely wrinkled, com- 



* This figure was made from an imperfect specimen, the wing being mutilated, 

 t See Barnes's description. 



| Mr Barnes says " ovately quadrangular ;" but the shell is evidently more tri- 

 angular, as his figure displays it. See Silliman's Am. Journ. Vol. VI. p. 278. 



