01' THE I'WMIM OF NA1AI)I>. Ill 



Barnes docs not mention, and is yellowish, not brownish. 

 This and the danaciformis are all 1 knovt which possess the 

 zig-zag markings, and they most resemble each other. 



1 2. I'm.. Pati lis. Plate Xll. fig. jo 



-• 



Testa ovatd, compressd, cuneiformi, inaquilaterali, obliqud, trans- 

 versa : umbonibus compressis ; valvulis sub-crassis; natibus svb-termi- 

 nalibus ; dents cardinaliparvo ; latt rati longoct svb-curvato ; margaritd 



albii. 



Shell ovate, compressed, wedge-shaped, inequilateral, oblique, trans- 

 verse, compressed on the umbones; valves rather thick; beaks nearly 

 terminal ; cardinal tooth small ; lateral tooth long and slightly curved : 

 nacre pearly white. 



Hab. Ohio. T. G. Lea. 



My Cabinet. 



Cabinet of T. (i. Lea. 



Cabinet of Prof. Vanuxem. 



Diam. -s. Length 1-1. Breadth 2- '• inches. 



Shell compressed, wedge-shaped, ovate, broad and flat; sub- 

 stance of the shell thick anteriorly and thin posteriorly, show- 

 ing the rays through it: beaks nearly terminal, slightly pro- 

 minent, approaching, and when perfect possessing slight 

 concentric undulations, generally decorticated ; ligament not 

 large, passirig from the point of the beaks; epidermis yellow- 

 ish brown, transversely wrinkled, marked with more or less 

 broad interrupted rays, apparently formed of fasciculi of hair- 

 like liiK •>: cardinal tooth short, and but slightly elevated, in 

 the left valve double and deeply cleft, in the right valve 

 emerging from a |>ii : lateral tooth long and slightly curved; 

 posterior cicatrices as well as anterior cicatrices distinct ; the 

 smaller posterior cicatrix situated against the lateral t * »* »t 1 1 at 

 its termination; dorsal cicatrices on the under part of the car- 

 dinal tooth; cavity of the beaks qoI deep I ml rounded; oacrt 

 thick and milk whin anteriorly, thin and iridesci at poste- 

 riorly. 



