8/5 CRETACEOUS PELECYPODA 



I do not uced to repeat here the importance of the study of the fossil forms 

 of Pelecypoda in order to attain this ohjcct of natural classification ; and I will 

 only append a table showing the different groups, &c., which I shall adopt in 

 the course of my monograph. The characteristics of each order, family, &c., will 

 be found in their respective places ; and the reason for doing this has already been 

 explained in the preface. I begin with wdiat I consider the highest order. 



Class,— PELECYPODA. 



I. Order,— PHOLADACEA. 



1. — Faviily FHOLADID^, (suh-fam. tebedininjE and froladismJ. 



2. „ GASTBOCSJENID^, (suh-fam. gastrocs^nin/e, clavagel- 



LIN/E, BRECRITIN^J. 



II, Order,— MYACEA. 



3. — Famihj IIYID^F, (suh-fam. corbulinje and myin^J. 



MACTRID^F, (suh-fam. lutrariin^ and mactrin^J. 



ANATINID^, (suh-fam. fandorin/E, thraciin^, anatinin/eJ. 



SAXICA riB^. 



GLA UCONOIIYID^. 



SOLENIDJE, (suh-fam. solenin^ and pharellinjeJ. 



III. Order,— TELLINACEA. 



Q.— Family FAFHIID^. 



10. ,, SCROBICULAFIIDJE, (suh-fam. cumingiinje and semelin.eJ. 



11. „ TFLLINID^F, (suh-fam. garin^, tellininm, and capsinmJ. 



12. „ BON ACID uJS. 



IV. Order,— VENERACEA. 



\2,.— Family FETBICOLID^F. 



l-i. „ VFNFllIBJE, (suh-fam. tapesin^e, veneris^, sunettix^, dosi- 



NIIN/eJ. 



15. „ OLOSSID^. 



16. . „ CYllENIDJE. 



17. „ CARDIIB^F, (suh-fam. cardtix^e and LYUNOCARDiiyjiJ. 



Y. Order,— CHAMACEA. 



\S.— Family VEETICOBBIID^. 



19. „ TBIBA CNIBJE. 



20. „ CUAMIBJE. 



21. „ CUAMOSTBEIBJE. 



22. „ UIPPUBITIB^E. 



