boniferous Formation of Belgium; 1 and S. Edelfelti, Kth. 

 fil. 2 from Queensland in general form, hut differs from tlie 

 first two in its tapering posterior portion, and from all 

 three by the very close nature of its radiating striae. 



Specific Characters.— Test transversely ovate, elongated 

 anteriorly and rounded posteriorly. The anterior border is 

 slightly uplifted, short, straight, making an acute angle 

 with the ventral margin, which is broadly rounded. Umbos 

 nearly centrally situated fairly prominent and twisted 

 anteriorly. Anterior adductor ImpressioD prominent, its 

 cast being sharply ridged upon its dor-'al herder. The 

 posterior adductor is shallow and situated high in the valve. 

 Pallial line not visible, and hinge structure unknown. The 



to the ventral margin. The spnees between the ridges are 

 smooth and deeply rounded. Anterior to the umbos, there 

 isan elongated cordate and somewhat concave escutcheon, 

 separated from the remainder of the valve by a prominent 

 rounded ridge, upon which the ornamentation doubles and 

 runs upwards towards the umbos nearly parallel to the 

 dorsal margin, which at its anterior extremity is elevated, 

 thus forming on the united valves a sharp ridge which 

 stands above the escutcheon. 



ness of united valves \ of an inch. 

 Loc. Barrier (D>. 





