,106 MYA. GAPER. 



striate, perlaceotis within: beaks nearer one end: hinge 

 with a bread notched tooth in both valves, and two lateral 

 plates in one valve and one in the other, all locking into 

 one another: length sometimes nearly two inches, and four 

 i:i breadth. 



It differs from the next, in having both the ends rounded, 

 and the beaks less prominent. 



In the river Kennel : rare. v. v. 



20. MyaPictorum. Painter's Gaper. 



Lister, pi. 147. f. 3 Da Costa, pi. 15. f. 4 Pennant, 

 pi. 46. f. lJFood, pi. 19. f. 3,4 Dorset Cat. pi. 12. f. 4. 



Mya ovalis. Donovan, pi. 89. 



Shell oblong-oval, produced and narrower at one end, 

 covered with a dark green skin, which in old shells becomes 

 nearly black, irregularly striate transversely, peiiaceous 

 within ; when shut the valves are closed in front, but a little 

 open ( at both ends : teeth as in the last species, and of 

 about the same size. 



Kapid rivers : rare. v. v. 



21. Mya ovata. Oval Gaper. 



Lister, pi. 147. f. 2fFood, pi. 19. f. 5 Donovan, 

 pi. 101, and 122. 



Shell oval, very convex, thick and brittle, much round- 

 ed at one end, produced and very narrow at the other, ir- 

 .regularly and coarsely wrinkled transversely, with some- 

 times faint longitudinal rays, covered with a green skin 

 which varies more or less to a dark-brown towards the 

 margin, under which it is of a fine opalaceous white color ; 

 inside perlaceous : beaks rather prominent j teeth as iu the 

 two last, and nearly the same size ; but it is narrower than 

 M. Batava, and broader than M. Pictorum. 



In rapid rivers, v. v. 



22. Mya margaritlfera. Pearl Gaper, Fig. 47. 



Lister, pi. 149. f. 4 Pennant, pi. 48. f. <2Da Costa, 

 pi. 15. f. 3 Donovan, pi. 73 Wood, pi. 23. f. 1 to o. 



Shell oblong-oval, thick, strong, covered with a black- 

 brown skin, rounded at one end and a little angular at the 

 other where it is sloping and depressed from the beaks to 



the 



