147 



ISOCARDIA concentrica. 



TAB. CCCCXCI— /g. 1. 



Spec. Char. Transversely elongate^ heart-shaped^ 

 concentrically sulcated ; shell thin. 



1 HE 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. 



