64 COyiCHYLlX— D J THY R A. 22. 



22. LVFRkRlk— LAMARCK. 



Testa transversa, ohlonga, tequivalvis, lateribus hiantihus. 



Cardo dente cochleariformi, cum dente trigono adjecto : 



lateralibus nnllis. Ligamentum internum. 

 Shell transverse, oblong, equlvalve, 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. 



ob!>nga LcTRARiA testd oblongd imequUaterali transversim rugoso- 

 striatd, latere anticn elongato angulato-truncato 

 Shell oblong inequilateral with rough transverse striae, elongated 

 and angularly truncated at the anterior end. 

 Tab. nost. 5, iig. 6. 

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



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

 Donovan, British Shells, iii. tab. 140 

 Linn. Trans, viii. p. 74. 

 Turton, British Fauna, p. 165. 

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

 Dillwyn, Descript. Catal. p. 146. 

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



