xl. CONCHYLIA— DJT//yj2^. 



9. medium, orbiculare, costis numerosis transversim striatis. 



orbicular, with numerous transversely striate ribs. 



10. laevigatum, ohovatum nitidum, costis obsoletis. 



obovate and glossy, with the ribs obscure. 



11. serratum, ohovatum nitidum sulphureum glaberrimum. 



obovate glossy and sulphur yellow, with the ribs 

 quite obliterated. 



42. ISOCARDIA. 



1. Cor, Isocardia. 



43. Mytilus. 



1. ungulatus, transversim rugosus, suhquadridentatus^ 



transversely wrinkled, with four or five teeth. 



2. edulis, lavis, subquadridentatus. 



smooth, with four or five teeth. 



3. incurvatus, crassus opacus incurvatus, subbidentatus. 



thick opake and incurved, with two or three teeth. 



4. pellucidus. diaphanus radiatus rectus subbidentatus. 



transparent radiate and straight, with two or 

 three teeth. 



44. MoDIOLA. 



1. Modiolus, oblonga solida, antici obliqui dilatata. 



oblong and solid, obliquely dilated at the anterior 

 side. 



2. Gibsii, foliaceo-barbata, foliolis hinc serratis. 



bearded with foliations which are serrate on one side. 



