102 



(Hemicardium, Cuvier), C. fragum (Fragum, Bolten), C. hystrix, [Cteno- 

 cardia, Adams), C. retusum [Lumdicardla, Gray), C. edentula, [Adacna, 

 Eichwald), C. pseudocardia [Monodacna, Eichvvald), and C. Bonaciformis 

 [Didacna, Eichwald). 



The Cardia have an unusually wide distribution both in depth and space. 

 In depth their place of habitation varies from tide-mark to a hundred 

 fathoms and more ; and in space their range extends from Greenland and 

 the Falkland Islands to the equator.* 



1. aculeatum, Linn. 



2. Adainsii, Reeve. 



3. alteruatum, Sow. 



4. angulatum, Lam. 



5. arcuatura, Mont. 



6. arenicolurn, Reeve. 



7. Asiaticuni, Brug. 



8. assimile, Reeve. 



9. attenuatum, Sow. 



10. aurantiacuin, Adams. 



11. auricula, Forsk. 



12. Australe, Sow. 



13. Australiensis, Reeve. 



14. Beechei, Adams. 



15. Belcheri, Brod. 



16. Belticum, Beck. 

 17- biangulatum, Sow. 



18. biradiatum, Brug. 



19. blandum, Gould. 



20. boreale, Reeve. 



21. Brasilianum, Lam. 



22. bullatum, id. 



23. Calif ornianum, Conr. 



24. Californiense, Desk. 



25. cardissa, Linn. 



26. Carditaeformis, Reeve. 



Species. 



27. Caspium, Eich. 



28. ciliare, Linn. 



29. colorata, Eick. 



30. consors, Sow. 



31. coronatum, Speng. 



32. costatum, Linn. 



33. crenulatum, Lam. 



34. Cuiningii, Brod. 



35. Deshayesii, Payr. 



36. Dionseuin, Sow. 



37. Donaciforme, Sckr. 



38. Dupuchense, Reeve. 



39. echinatum, Linn. 



40. edule, id. 



41. Eichwaldii, Reeve. 



42. elatum, &??£. 



43. elegantulum, Beck. 



44. Elenense, $>«?. 



45. elongatum, Brug. 



46. enode, Sow. 



47. erinaceum, Zara. 



48. exiguum, Gmel. 



49. fasciatura, Mont. 



50. femiginosnm, Reeve. 



51. fimbriatum, Wood. 



52. fornicatum, ^ow. 



53. foveolatum, flow. 



54. fragile, Reeve. 



55. fragum, Zz'wra. 



56. Grcenlandicum, Ck. 



57. graniferum, 5ro^. 



58. hemicardium, Linn. 



59. hians, Z?/*oc. 



60. hiulcum, Reeve'. 



61. hystrix, £rf. 



62. Icelandicum, C%m. 



63. imbricatum, Sow. 



64. impolitum, i<£ 



65. incamatum, Reeve. 



66. isocardia, Linn. 



67. Kalamantinum, Adams. 



68. lacunosura, Reeve. 



69. leevigatum, Zwm. 



70. lseviuscula, _Efo/i. 



71. Lamarckii, Reeve. 



72. latum, itom. 



73. leucostoma, id. 



74. lima, Reeve. 



75. lyratum, #02#. 



76. maculatum, id. 



77. maculosum, Wood. 



78. magnum, Born. 



* " We find the great central assemblage of Cockles in the Indian Ocean, a region where about 

 a third of the species are congregated. Around this centre tbe number of specific forms dimi- 

 nishes, though found in every sea. They are most plentiful everywhere within the tropics, and 

 diminish as we proceed northwards and southwards ; but some of the forms most prolific in in- 

 dividuals, and most gregarious in habit, are present in cold climates, and make up by abundance 

 for the absence of variety. The genus contains several remarkable abnormal forms ; some of the 

 most singular are to be found in the Caspian and other relics of the great Aralo-Caspian Sea, — 

 the demonstration of which mighty inland ocean is among (he finest discoveries of Sir Roderick 

 Murckisou." — Forbes and Hartley, Brit. Moll., vol. ii. p. 3. 



