xvi. CONCHYLIA— D/rHYi?^. 



29. Stbigilla. — Testa hifaridm anguloso-striata. 



Shell with angular striee in opposite directions. 

 27. Tellina. — Testa anticS jlexuosa, dentibus subbinis. 



Shell flexuous at the anterior side, with two 



teeth in one or both valves. 



41. Cardium. — Testa cordata, umbonibus contiguis, dentibus duobus 



cum lateralibus in utrdque valvd. 

 Shell heart-shaped, the beaks close together, with 

 two teeth and two lateral ones in both valves. 



42. IsoCARDiA. — Testa cordata, umbonibus remotis convolutis, 



dentibus duobus cum laterali unico antico in utrdque 



valvd. 

 Shell heart-shaped, the beaks remote and convo- 

 lute, with two teeth and a single lateral tooth on 

 the anterior side in each valve. 



C. 



Ligamentum internum. 

 Ligament internal. 



* Cardo edentulus. 

 Hinge without teeth. 

 50. Anomia. — Valva inferior basi perforata. 



The under valve perforated at the base. 



