EXPLANATION OP PLATES. 439 



FIGURE. PAGE. 



25, 26. Hippurites radiosns, Desm. 25. Interior of lower 

 valve, ^. 26. Upper valve (restored). Lower Chalk; 

 St. Mamest, Dordogne. a, a, adductor impressions 

 and processes ; c, c, cartilage pits ; t^t' , teeth and 

 dental sockets ; u, umbonal cavity ; p, orifices of 

 canals ; Z, ligamental inflection ; m, muscular, w, 

 siphonal inflection, . . . . . . . 204 



21, 28. Hippurites Toucasianus,d'Orb. 27. Upper valve, -1. 

 28. Lower valve, with mould ; Z, ligamental, m, mus- 

 cular, n, siphonal inflections ; x, fracture, showing- 

 canals ; c, cartilage ; w, left umbo ; the arrows indi- 

 cate the probable direction of the branchial currents, 203 



29, 30. Hippurites sulcatus, Defrance. Cret.; France, . 203 



3L. Radiolites alata, d'Orb., 205 



32, 33. Radiolites mammillaris. Math., ^. 32. Interior of 

 lower valve. 33. Interior of upper valve, L. Chalk; 

 S. Mamest, Dordogne. Z, ligamental inflection ; m, 

 pallialline; c, c, cartilage pits ; a, a, adductor impres- 

 sions and processes ; i, teeth and dental sockets, . 205 



34, 35. Radiolites mammillaris. Math. Side views of the 

 upper valve. Z, ligamental inflection ; i, teeth ; a, a', 

 muscular processes, ....... 205 



36, 31. Radiolites Haeninghausii, Desm. One-half size. 

 Chalk. 36. Upper, 31. Side view, it, umbo of left 

 valve ; r, right umbo ; Z, ligamental groove ; c. c, 

 cartilage ; a-, anterior adductor muscle ; a', posterior, 205 



38. Biradiolites caTialiculatus. p, point of attachment ; Z, 



ligamental groove ; a, a, corresponding areas, . . 206 



39. Sphserulites unisulcatus, Matheron, .... 206 



Plate 119. 



40. Lucina Jamaicensis, Linn. West Indies, . . .210 



41. Lucina (C^'clas) divaricata, Linn. West Indies, .210 



42. Lucina (Codakia) tigerina, Lam. West Indies, . . 210 



43. Lucina (Miltha) Childreni, Gray. Brazil, . . . 210 



44. 45. Lucina (Myrtea) scabra, Lam. California, . . 210 

 46, 53. Lucina (Here) Richthofeni, Gabb. Tert. ; Cal. . 210 

 41. Loripes edentula, Linn. West Indies, . . . 211 



48. Cryptodon flexuosus,Montf. England, . . . 211 



49, 50. Philis Cumingii, Fischer. Moluccas, . . .211 



51. Corbis flmbriata, Linn. Fiji Islands, .... 212 



52. Corbis (Sphsera) corrngata, Sowb. Neocomian; Eur., 212 

 54. 55. Corbis (Sphaeriola) Mellingi, Hauer. Trias; Eur., 213 

 56. 51. Corbis (Mutiella) coarctata,Zitt. Turonian; Gosau, 212 



58. Unicai'dium impressum, Morris and Lycett, . . 213 



59. Fimbriella laevigata, Sowb. Cretaceous; England, . 213 



