43. Janellii, Kiener. 



44. kiosquiformis, Buchs. 



45. lapillus, Lam. 



46. lineata, id. 



47. luteostoma, Besh. 



48. Madreporarum, Sow. 



49. mancinella, Lam. 



50. melones, Dticlos. 



51. m\vc'\cvci&, De Blainv. 



52. musiva, Kiener. 



53. Neritoidea, Des^. 



54. mix, Reeve. 



55. patula, Za»i. 



56. persica, Lam. 



57. pica, i)^. Blainv. 



58. planospira, iem. 



59. pupillata. Reeve. 



60. Qiioyi, 2V/. 



61. Kudolplii, Lam. 



62. rustica, /W. 



63. sacellura (Murex), Ch. 



64. Scalariformis, Lam. 



65. scobina, Q?<oy. 



66. septentrioiialis. Reeve. 



67. speciosa, Valenc. 



68. spiralis, Reeve. 



69. squamosa, i«OT. 



70. S(iuamulosa, Reeve- 



71. succincta, i«?rt. 



72. textilosa, zr/. 



73. thiarella, id. 



74. trigoiia. Reeve. 



75. trochlea, i«m. 



76. tumidosa, Reeve. 



77. imdata, iflw.. 



78. uriifascialis Lam. 



79. violacea, Kiener. 



80. xanthostoma, ^rot?. 



PuRPUiiA APERTA. Plate. 6. Fif?. 30. Shell showing its depressed spire, 

 dilated aperture, and flattened columella. 



Genus 20. COLUMBELLA, Lamarck. 

 Animal ; disc elongated and narroiv, truncated and a little dilated 

 in front, hind extremity furnished with a small horny oper- 

 culum, head small, fattened, trianyidar, prolonged into two 

 conical cylindrical tentacles, pedunculated to about a third of 

 their extent, at the summit of which portion are the eyes ; trunk 



rather long. 

 Shell ; S7nall, ovately oblong or triangular, sometimes fusiform, 

 columella arched and denticulated, rarely smooth ; outer lip 

 thickened, swollen, gibbous and most frequently denticulated in 

 the middle. 



The genus Columhella includes a very numerous series whose shells are 

 uniformly small, and distinguished by a greater or less number of plait-like 

 denticles on the lip and columella after the manner of Ricimda. From the 

 circumstance of Lamarck having confounded a few of the small Mitres 

 with the Columhella, he was induced to refer the genus to the family Colu- 

 mellata, assuming the existence of a plaited columella ; the plaits by which 

 the genera of that family are characterized are, however, of very difPerent 

 structm-e, from the protuberances which are here designated plait-like 

 denticles ; the first being developed on the columella throughout its entire 

 growth so as to form a continuous winding of spiral plaits around the 

 columella axis, whilst the last are merely developed along the inner side of 

 the columella, on arriving at maturity. 



