147 
1S0CARDIA concentrica. 
TAR. CCCCXCI .—Jig, 1. 
Spec. Char. Transversely elongate, heart-shaped, 
concentrically sulcated ; shell thin. 
The depth and length are nearly equal, and considerably 
less than the width ; the general form is a nearly regular 
oval, rendered heart-shaped by the projecting, neatly 
incurved beaks ; the sulci are numerous, not deep, they 
extend the whole width, and gradually become more 
distant as they approach the edge ; the surface, except- 
ing that it is thus sulcated, is smooth and regular. 
This handsome fossil is found in the Cornbrash Lime- 
stone at Bulwick, in Northamptonshire. We are in- 
debted to John Hogg, Esq., of Leeds, for the knowledge 
of it. 
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