ARNOLD — THE PALEONTOLOGY AND STRATIGEAPHY OF SAN PEDRO. 77 



MOLLUSCA (Continued). 



Genus Pauomya Gray 183 



136. ampin D.vi.i 183 



SUPERFAMII.Y AJ>ESMACEA .' 183 



Famili/ XXXIX. Pholadida. 183 



Suli/amily PholadUtm 183 



(iouus ZirphiBa Leach 183 



1,37. gabbii Tryon 184 



SuhfaniHy Jouanni'linii- 184 



Genus Pholadidea Goodall 184 



Subgenus Pholadidea, s. » 184 



Section Penitella Valenciennks 184 



138. (P.) peuita Conrad 184 



CLASS VI. SCAPHOPODA 185 



Order Soi.enoconchia 185 



Famili/ XL. Dentaliidui 185 



Genus Dentalium Linne 185 



139. hexagouum Sowerisy 185 



140. iudiauorum Carpenter 186 



141. pseudoliexagonum Dall 186 



14^. semipolitum Brouerip & Sowerby 187 



Genus Cadulus Phii.ii'PI 187 



143. uiteutior Carpenter 187 



CLASS VII. GASTROPODA 188 



Order Opi.stiioiiraxciiiata 188 



Family XLI . A clitonidiR 188 



Genus Act.-eon Montfort 188 



144. traskii Stearns 188 



Subgenus Rictaxis Dall 188 



145. (R.) punctoccelata Carpenter 189 



Family XLI [ . Tornalinidie 189 



Genus Toiuatiua A. Adams 189 



146. cerealis Goui.d 189 



147. cnlcitella Goold 190 



148. exiniia Baird 190 



149. harpa Dall 191 



Genus Volvula A. Adams 191 



150. cylindrica Carpenter 191 



Family XLI 11 . Scaphandrida; 192 



Genus Cylicbna Loven 192 



151. alba Brown 192 



Family XLI V. Bullid,i' 193 



Genus Bulla Linne 193 



152. punetulata A. Adams 193 



153. quoyi Gray 193 



Genus Haminea Leach 194 



154. virescens Sowerey 194 



Order Pulmonata 194 



Suborder Stylommatophora 194 



SUPERFAMILY MONOTREMATA 194 



Family XL V. Ilelicida; 194 



Genus Helix Linne 194 



Subgenus Epiphragmophora Strobel 194 



155. (E.) sp. indet 195 



SUPERFA MIL Y HYGROPHILA 195 



Family XL VI. Limnaidce 195 



Subfamily Plaiiorbimii 195 



Genus Planorbis Guettakd 195 



156. tumidus Pfeiffer 195 



157. vermicularis Gould 195 



