EXPLANATION OF MAP. 



The geographical position of each species is represented by a 

 black circle inclosing a number, which refers to the following 

 alphabetical list of names : 



(The fact is recognized that some of the names here employed probably repre- 

 sent developmental phases of other species, but as it is impossible with our 

 present knowledge to ascertain of how many such names this is true, the com- 

 monly accepted designations are therefore employed.) 



1. Agulhasia Davidsoni. 



33. 



Glottidia albida. 



2. Atretia Brazieri. 



34. 



G. 



Antillarum. 



3. A. 



gnomon. 



35. 



G. 



Audebardi. 



4. Bouchardia rosea. 



36. 



G. 



Palmeri. 



5. Cistella Barrettiana. 



37. 



G. 



pyramidata. 



6. C. 



cistellula. 



38. 



G. 



semen. 



7. C. 



cuneata. 



39. 



Gwynia capsula. 



8. C. 



Kowalevskii. 



40. 



Kraussina Atkinsoni. 



9. C. 



lunifera. 



41. 



K. 



cognata. 



10. C. 



lutea. 



42. 



K. 



Davidsoni. 



11. C. 



neapolitana. 



43. 



K. 



Deshayesi. 



12. C. 



Schrammi. 



44. 



K. 



Lamarckiana 



13. " 



' ' var. rubrotincta. 



45. 



K. 



pisum. 



14. C. 



Woodwardiana. 



46. 



K. 



rubra. 



15. Crania anomala. 



47. 



Laqueus calif ornicus. 



16. 



" var. alba. 



48. 



(< 



" var 



17. C. 



japonica. 







verensis. 



18. C. 



Pourtalesi. 



49. 



L. 



pictus. 



19. C. 



Suessi. 



50. 



Lingula Adam si. 



20. C. 



turbinata. 



51. 



L. 



affinis. 



21. Discina striata. 



52. 



L. 



anatina. 



22. Discinisca Antillarum. 



53. 



L. 



exusta. 



23. D. 



atlantica. 



54. 



L. 



hians. 



24. D. 



Cumingi. 



55. 



L. 



hirundo. 



25. D. 



lsevis. 



56. 



L. 



jaspidea. 



26. D. 



lamellosa. 



57. 



L. 



lepidnl:i. 



27. D. 



stella. 



58. 



L. 



Murphiana. 



28. Dys- 



^olia Wyvillii. 



59. 



L. 



parva. 



29. Eucalathis ergastica . 



60. 



L. 



Reevii. 



30. E. 



Murray i. 



61. 



L. 



smaragdina. 



31. E. 



tuberata. 



62. 



L. 



tumidula. 



32. " 



11 var. mediterianca. 



63. 



Liothyrina arctic.! 





1 



6 







Vancou- 



