450 NEAV GENUS AND SOME NEW SPECIES 



and beautiful species. It is peculiar in its very much com- 

 pressed beaks, and in its greatest diameter being but a short 

 distance above the basal margin. 



5. Symphynota Co3ipressa. Plate XH. fig. 22. 



Testa transversim elongatd, incBquilaterali, valde compressa, ellipticd ; 

 valvulis tenuibus ; natibus sub-prominulis, imdulatis ; dente cardinali 

 prominente ; laterali parvo. 



Shell transversely elongated, inequilateral, compressed, elliptical ; 

 valves thin ; beaks scarcely prominent, undulated ; cardinal tooth promi- 

 nent; lateral tooth small. 



TT 1 5 Ohio. T. G. Lea. 

 ^^^- I Norman's Kill, near Albany. Dr Eights. 



My Cabinet. 

 Cabinet of Prof. Vanuxem. 



Cabinet of Dr Eights. 

 Cabinet of P. H. Nicklin. 

 Cabinet of the Academy of Natural Sciences. 

 Cabinet of the New York Lyceum. 

 Diam. -S, Length 1-7, Breadth 2-8 inches. 



Shell transverse, much compressed, elliptical ; substance of 

 the shell rather thin ; beaks slightly elevated, not decortica- 

 ted, beautifully crowned with small double concentric undu- 

 lations, points of the beaks almost white ; ligament concealed 

 within the valves ; dorsal margin rather elevated posteriorly 

 to the beaks ; posterior margin sub-angular ; posterior basal 

 and basal margins curved ; anterior and anterior dorsal and 

 basal margins rounded ; epidermis olive-green, slightly wrin- 

 kled and glabrous ; radiations over the whole disk ; cardinal 

 tooth prominent and curved, in the left valve with three pro- 

 tuberances, the posterior the highest, sloping to the end of the 

 lateral tooth, the anterior the lowest ; in the right valve one 

 rather large, which closes between the first and second of the 

 left; lateral tooth short and nearly straight, passing from 



