64 GO^GBYLIA—DITHYRA. 22. 



22. LUTHAmA—LAMARCK. 



Testa transversa, oblonga, cequivalvis, lateribus hiantibus. Cardo 



dente cochleariformi, dente trigono adjecto : lateralibus nullis. 



Ligamentum internum. 

 Shell transverse, oblong, equivalve, open at both the sides. Hinge 



with a spoon-shaped tooth and an adjacent triangular one : lateral 



teeth none. Ligament internal. 



This genus has been very judiciously made distinct from the 

 Mactra, both on account of the absence of lateral teeth, and the 

 more considerable gape at one or both of the sides. The general 

 outline is also transversely oblong ; and the habitat is about the 

 entrance of rivers. 



oUonga. LuTRARiA testd oblongd, incequilaterali transversim rugoso-striatd, latere 

 antico elongato angulato-truncato. 

 Shell oblong inequilateral with rough transverse striae, elongated 

 and angularly truncated at the anterior end. 

 Tab. nost. 5, fig. 6. 

 Mactra hians. Montagu, Test. Brit. p. 101. 



Pennant, Brit. Zool. iv. p. 196. 

 Donovan, British Shells, iii. tab. 140. 

 Ldnn. Trans, viii. p. 74. 

 Turton, Brit. Fauna, p. 155. 

 Dorset Catal. p. 33, tab. 2, fig. 4. 

 Dillwyn, Descript. Catal. p. 146. 

 Turton, Conch. Diet. p. 85, fig. 41. 



