CO'^GKYLIA—DITHYRA. 42. ' 193 



serrate : the longitudinal striae quite invisible, except when examin- 

 ed by a high magnifying power, when they appear to be equally 

 distributed over the whole surface. 



42. ISOCARDIA— L^M^ECiir. 



Tenta cBquivalvis, cordata, ventricosa ; umbonibus remotis, convolutis 

 postici secundis. Cardo dentibus duobus compressis obliquis pene- 

 trantibus, unico sub umbonem subrecurvo : laterali remoto, antico. 

 Ldgamentum externum. 



Shell equivalve, heart-shaped, very tumid ; with the beaks remote 

 convolute, and both pointing to the hinder side. Hinge with two 

 flat oblique penetrating teeth, one of them placed under the beak 

 and a little recurved : and a remote lateral tooth on the anterior 

 side. Ligament external. 



IsocARDiA testa globoso-cordatd Iwviusculd. ^"^ 



Shell globular heart-shaped, and nearly smooth. 



Tab. nost. 14. 

 Chama Cor. Linn. Syst. Nat. p. 1137. 



Gmelin, Syst. p. 3299. 

 Turton, Linn Syst. iv. p. 244. 

 Pennant, Brit. Zool. iv. p. 214. 

 Montagu, p. 134, and Suppl. p. 50, 

 2c 



