VENUS GRATA. 



SPECIFIC CHARACTER. 



Granulated with longitudinal and transverse striae : whi- 

 tish, with dotted rays of pale ferruginous and blackish ; 

 blackish oblique lines before. 



DESCRIPTION. 



Shell transversely suboval, convex, with very numerous, 

 close set, longitudinal striae ; those on the anterior two- 

 thirds of the shell have a slight appearance of folds, or as 

 if each one originated beneath the one posterior to it in a 

 somewhat imbricated manner ; these stride are granulated 

 by very numerous transverse striae, which are more obvi- 

 ous on the posterior third of the shell, and almost obsolete 

 on the middle : colour whitish, somewhat tinged with 

 green towards the umbones, broadly radiated with very 

 pale ferruginous and dusky purplish, with numerous dots 

 and abbreviated lines of purple-black : anterior margin 

 with transverse, oblique, purple black lines : posterior mar- 

 gmpale ferruginous : lunule dusky, bounded by an impres- 

 sed line : umbones not very prominent : hinge margin nearly 

 rectilinear, terminated anteriorly by an obtuse angle ; in 

 this part the edge of the left valve laps a little over and 

 conceals the corresponding part of the edge of the right 

 valve : ligament deeply seated : posterior margin round- 

 ed : lunule impressed, distinct by an impressed line : with- 

 in, very broadlyjmargined with violaceous; margin crena- 

 ted : intermediate tooth cmarginatcd at tip : anterior tooth 

 of the left valve also cmarginated. 



