198 LIST OF FIGURES. 



Figure, Name. Page. 



29. Septifer hifurcatus, Eve 75 



30. Adulafalcata, Gld 75 



31. Surcula Carpenteriana, Gabb 76 



32. Goniohasis nigrina, Lea 79 



33. Goniohasis plicifera, Lea 79 



34. Physa heterostropha, Say 81 



35. Helisoma trivolvis, Say 81 



36. Limnophysa palustris, Mull 82 



37. Limnsea stagnalis, Linn 82 



38. Anodonta Californiensis, Lea 83 



39. Anodonta angulata, Lea 85 



40. Olivella biplicata, Sby 87 



41. Psammobia ruhro-radiata, Niitt 88 



42. Macovia secta, Conr 89 



43. Tapes staminea, Conr 90 



44. Saxidomus Nuttalli, Conr 90 



45. Donax CaJifornicus, Conr 91 



46. Glycimeris generosa, Gld 92 



47. Lunatia Lewisii, Gld 93 



48. Littorina planaxis, Nutt 98 



49. Littorina scutulata, Gld 98 



50. Chlorostoma funehrale, A. Ad. 98 



51. Chlorostoma brunneum, Phil. 99 



52. Calliostoma cosiatum, Mart 99 



53. Calliostoma a7inidatum, Mart 99 



54. Leptonyx sanguineus, Linn 100 



55. Pomaulax undosus, Wood 101 



56. Trochiscus Norrisii, Sby 101 



57. Cryptochiton Stelleri, Midd 104 



58. Tonicella lineata, AVood 104 



59. Stenoradsia Magdalenen&is, Hds 104 



60. Mopalia ciliata, Sby 105 



61. Mopalia lignosa, Gld 105 



62. Purpura saxicola, Val 105 



