XVI LIST OF ENGRAVINGS. 



Page 



An Operculum, or Lid 123 



Barrier of a Snail 124 



Arrangement of the Membrane in Mother-of-pearl .... 126 



Section of the Horns of a Snail . . .130 



The Vermetus 143 



The Chiton 145 



The Clio borealis 147 



The Octopus vulgaris 153 



Suckers of Cephalopods 156 



The Onychoteuthis 158 



Jaws of Cephalopods 159 



Eye of the Octopus 165 



The Nautilus 168 



Argonauta argo 172 



Another representation of ditto ] 73 



Section of the Pearly Nautilus ] 75 



Tentacula of Cuttle-fish ] 79 



Migration of Eggs 1 84 



A Fossil 187 



Matlock Incrustation 194 



Genuine Petrifaction 196 



Nummulite 198 



Flutings and Bosses of an Ammonite 206 



Section of an Ammonite 207 



Belemnite , .... 208 



Pen of a Cuttle-fish 209 



