138 SPECIFIC 



PLATE VI. 

 Fig. 1. Hinge of Mactra lutraria. 



Fig. 2. Mactra stultorum. 



Shell subdiaphanous, smooth^ obsoletely ra- 

 diate, purplish within ; area gibbous. 



Lister Conch, tab. 251. 



Specimen pale brown inclining to cinereous, with 

 paler rays, finely striate transversely. 



Inhabits the English coast 



Fig. 3. Hinge of DoNAX Scortum, 



Fig. 4. DoNAX denticulata. 



Shell very obtuse on the anterior side ; lips trans- 

 versely wrinkled^ margin denticulate; shell striate 

 longitudinally. 



Lister Conch, tab. 376. fig. 218, 219. 



Specimen white with obsolete purple rays, area 

 cordate ; fore part strongly marked with decussate 

 striae. 



Inhabits the European and American seas. 



