Fig. 22. Cyclas rivicola. 



a. inner view of the valves 

 shewing the hinges. 



23. Cyrena Syria;, 

 a. b. the two hinges. 



24. Capsa. 

 a. b. the two hinges. 



25. Lucina Pensylvanica. 



26. Corbis. 

 a. b. the two hinges. 



27. Donax. 

 a. the hinge. 



28. Cytheria. 

 a. b. the two hinges. 



PLATES. 



Fig. 29. Venus. 



a. the hinge. 



30. Venus, 

 a. the hinge. 



31. Tellina suleata. 



32. Venericardia imbricaia. 



33. Cyprina Islandica. 



34. * Astarte planata. 



35. Crass ina. 

 a. b. the two hinges. 



36. Tellinides Timorensis . 

 a. b. the two hinges. 



37. Loripes. (Lucina lactea.J 



CARDIACEiE. ARCACEiE. 



Fig. 38. Cardimn. 



a. b. the two hinges. 



39. Isocardia cor. 



a. b. the two hinges. 



40. * Hiatella arctica. 



a. inner view of the opposite 

 valve 



4 1 . Cardita calyculata . 

 a. the hinge. 



42. Cypricardia Guinaiea. 



43. * Byssomia. (Mytilus Pho- 

 ladis.) 



44. Area. 



TRIGONEiE. TRIDACNEJE. 

 Fig. 45. Pectunculus. 



a - 



a. inner view shewing the 

 hinge. 



46. Nucula Placentina. 



a. inner view shewing the 

 hinge. 



47. Cucullaiaauriculifera. 

 a. inner view. 



48. Trigonia pectinata. 



a. hinge of the opposite valve. 



49. Cast alia ambigua. 



50. Hippopus maculatus . 

 a. the hinge. 



5 1 . Tridacna serrifera 

 a. b. the two hinges. 



