92 



GEN. IX. 

 MACTRA. 



Mmal a TETHYS. 



SHELL: bivalve: valves equal, inaequllateral. 



Hinge: middle tooth complicated with an adjacent 

 groove, or pit; lateral teeth remote, inferted into the op- 

 pofite valve. 



1. 

 Soi.idj^. Madra folida, Z.w. 5>j^. p. 1126.— G/Hc/. SjyyZ.p 3259.13. 



Br. Zool t. 51. f. 43. A.— t. 52. f. 43. 

 Chem. Conrh. vi. t. 23. f.229. 230. 

 Lifier Conch, t. 253. f. 87.— Id. Angl. t. 4, 



f. 24 

 Pult- Cat. Dorfet.p. 31. 

 Don. Br. Shells, ii. t. 61. 

 Turt, Lin. iv. p. 211. 

 Trigonella zonaria. Da Cojiap. 197. t. 15. f. 1. 1. 

 Trigonella Gallina. Id. p. 199. t. 14. f. 6. 6. 



M. with a flrong fub-triangular (liell, of a yellowifli- 

 white colour ; with a few concentric ridges, fides equal ; 



