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. PateHacitrullusGld. Expl. Exped., ... 86 



Plate 29. 



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



44-46. Patella co?rulea 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 noveniradiatus Q. Original, . . 146 



Plate 31. 



59, 60. Patella mexicana Brod. 5 nat. size. Original, . . 108 



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



62. Dentition, from Dall., 108 



Plate 32. 



63-66. Helcioniscus ardositeus 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. Acmoea hieroglyphica Dall. A. J. C, . . .49 

 80-82. Acm?ea peramabilis Dall. Original, . . .23 

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

 86, 87. Acm?ea lima Rve. Conch. Icon., . . . .60 

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

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

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

 96-98. Acmrea 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., . . .34 



3-8. A cniiea variabilis Sowb. Original, . . . .34 



9, 10. Acmtea pretrei Orb. Amer. Merid., . . . .33 



