ARCA LIENOSA. 



DESCRIPTION. 



Shell rather thin, transversely oblong ; ribs about forty, 

 somewhat flattened and much broader than the interven- 

 ing spaces which are very narrow, and with a longitudinal 

 impressed line, particularly on those of the posterior mar- 

 gin, which are almost bifid ; and with numerous slightly 

 elevated transverse lines, which being divided by the lon- 

 gitudinal stria3 appear granulated : heak but little promi- 

 nent, and nearly opposite to the posterior third of the 

 length of the hinge margin : area narrow and elongated : 

 hinge margin rectilinear, angulated at each extremity ; 

 teeth numerous, small ; posterior margin obliquely round- 

 ed inwards, no part of it extending further backward than 

 the angle: anterior margin obliquely truncate: inner 

 margin crenate. 



OBSERVATIONS. 



A fossil shell from the same locality as the preceding, 

 and also sent to me by Mr. Elliott. 



REFERENCE TO THE PLATE. 



Fig. 1, Exterior and Interior views. 

 PJ. 36. 



