240 DESCRIPTION OF 



Shell elliptical, compressed, inequilateral, angular behind; substance of the shell thick; beaks prominent; 

 epidermis yellowish brown, shining; cardinal teeth small; lateral teeth long and curved; nacre white and 

 iridescent. 



Hab. Ohio Canal, twelve miles below Columbus. Dr. Jay. 



Cabinet of Dr. Jay. 

 Diam. .9, Length 1.4, Breadth 2.2 inches. 



Shell elliptical, compressed, inequilateral, angular behind, carinate on the 

 umbonial slope; substance of the shell thick; beaks prominent, ligament rather 

 short and thick; epidermis yellowish brown, darker and wrinkled on the pos- 

 terior slope; cardinal teeth small, double in both valves; lateral teeth very long 

 and curved; anterior cicatrices distinct; posterior cicatrices distinct; dorsal 

 cicatrices placed under the plate between the cardinal and lateral teeth ; cavity 

 of the shell shallow; cavity of the beaks small and angular; nacre white and 

 iridescent. 



RemarJcs. — A single specimen of this shell only is before me. It is without 

 rays. The eroded state of the beaks prevents our knowing if it be undulate at 

 the tip. In outline it resembles some varieties of JJ. complanatus. In the flat- 

 ness of the sides it is allied to TJ. phaseolus, Hild. But it differs entirely from 

 that species in not being flattened towards the beaks and in being without 

 rays. 



Anodonta Montezuma. Plate 23, Fig. 55. 



Testa obovatd, subinflata, valde incequilaterali; valvulis tenuihus; natibus prominentibus ; epidermide 

 luted viridique, rugosd; margarita alba et iridescente. 



Shell obovate, rather inflated, very inequilateral; substance of the shell thin; beaks prominent; epi- 

 dermis yellow and green, rough ; nacre white and iridescent. 



Hab. Central America. Dr. Jay. 



Cabinet of Dr. Jay. 

 Diam. .6, Length 1.1, Breadth 1.6 inches. 



Shell obovate, rather inflated, very inequilateral, rounded before and behind; 

 substance of the shell thin; beaks prominent; ligament short and thin; epider- 

 mis yellow and green, rough; anterior cicatrices distinct ; posterior cicatrices 

 confluent ; dorsal cicatrices none ; cavity of the shell rather deep and rounded ; 

 cavity of the beaks very shallow ; nacre white and iridescent. 



