178 REFERENCE TO PLATES. 



PLATE 28. 



FIGURE. PAGE. 



35, 36. Helcioniscus enneagonus Rv. Couch. Icon., . . 152 



37, 38. Patella longicosta. Conch. Icon., . . ... 107 



39-41. Patella citrullus Old. Expl. Exped., . 86 



PLATE 29. 



43. Patella rustica Rv. (reduced). Conch. Icon., . .105 



44_46. Patella coerulea v. lowei Orb. Original, . . .84 

 47.49. Patella scabra Gld. Expl. Exped., ... 16 



50-52. Patella piperita Gld. Expl. Exped., . 87, 88 



PLATE 30. 



53, 54. Helcioniscus sanguinans Rv. Conch. Icon., . . 151 



55-58. Helcioniscus novemradiatus Q. Original, . .146 



PLATE 31. 



59, 60. Patella mexicana Brod. \ nat. size. Original, . . 108 



61. Sculpture of a young specimen. Original, . . . 108 



62. Dentition, from Dall., ... .108 



PLATE 32. 



63-66. Helcioniscus ardosiseus H. & J. Original, . .124 



67-69. Helcioniscus melanostomus Pilsbry. Original, . 151 



PLATE 33. 



70, 71, 73. Acmsea carpenteri Pils. Original, . . .39 



72. Acmsea carpenteri. Interior of a young specimen, . . 39 



74. Teeth of Pectinodonta arcuata Dall. Blake Rep., . . 6 



75. Basal plate, the cusp removed, of P. arcuata. Blake Rep., 6 



76. Pectinodonta arcuata Dall. Blake Rep., ... 6 

 77-79. Acmsea hieroglyphica Dall. A. J. C., 49 

 0-82. Acmsea peramabilis Dall. Original, . . .23 

 83-85. Scurria mesoleuca Mke. Original, . . . .64 

 86, 87. Acmsea lima Rve. Conch. Icon., . . . .60 

 88-90. Acmsea dorsuosa Gld. TYPE. Original, . . .45 

 91, 92. Acmsea uncinata Rv. Conch. Icon., . . . .61 

 93-95. Acmsea conoidalis Pse. Original, . . . .46 

 96-98. Acmsea garrettii Pils. Original, . . . .47 

 99. Acmsea vernicosa Cpr. Original, . . . . .28 



1-3. Acmsea subrotunda Cpr. Original, . . . .28 



PLATE 34. 



1-2. Acmsea variabilis Sowb. Conch. Icon., 



3-8. Acmsea variabilis Sowb. Original, . . . .34 



-9, 10. Acmsea pretrei Orb. Amer. Merid., . . . .33 



