19. Bacuh tes gigas. 



20. Planospirites ostracinus. 



21. Hippurites cornu-copia'. 



22. Belemnite. 



23. Siderolites calcitrapoides . 



24. Section of a Belemnite. 



25. Orthoceratite . 



26. Hippurite with a gutter, c. 



27. Hippurite with a siphon. 



28. Under view of the operculum of a Hippurite, shewing the two prolonga- 



tions resembling a hinge. 



29. Belemnite. 



30. Section of an Orthoceratite with a siphon passing through the axis. 



31. Hippurite with a gutter, a. and a siphon, b. 



32. Lituites Breynii, found in the marble of OEland : the shaft or straight 



part extends in a length equal to the depth of the Plate, gradually 

 enlarging towards the base. 



33. Hippurite, the operculum pierced with two eyes. 



34. 35. Orthoceratites with a siphon towards the edge or periphery. 



