UST OF IlL^USlYiAnONS. 



PAGE 



Fig. 64. Veliger. Larva of a Mollusc .... 211 



„ 66. The Scallop-shell 213 



„ 66. The Pilgrim's Scallop-shell . . . .214 



,, 67. Shells of Siphoniate Molluscs, the Pholas and 



the Eazor-shell 21.5 



„ 68. The Gaper-shell .... . . 216 



„ 69. The Sea Mussel ... ... 217 



„ 70. Shell of the Common Cockle . . . 217 



„ 71. Shell of the Fresh-water Mussel '. . . 218 



„ 72. Shell of the Biver Mussel 218 



„ 73. The Tusk-shell 219 



„ 74. The Sea-Ear 220 



„ 75. Examples of Holostomatous Gasteropoda : the 

 Wimble-shell ; the Wentle-trap ; the River 



Snail, with its operculum and odontophore . 221 

 „ 76. Shells of Siphonostomatous Gasteropoda : the 



Fountain-shell and the Money-cowry . . 223 

 „ 77. Shells of Siphonostomatous Gasteropods : 



Venus'-Comb ; Spindle-shell ; Whelk . . 224 

 „ 78. Shells of fossil forms of Tetrabranchiate 



Cephalopods : Turrilites, Geratites, Ammonites 227 



„ 79. Pearly Kautilus 229 



„ 80. Dibranchiate Cephalopods : the Squid ; the 



shell of the Paper Nautilus . . .230 

 „ 81. Shell of Terehratula, side view . . . .232 



„ 82. Shell of Terebratula ... .233 



„ 83. Simple Ascidian ... ... 235 



„ 84. Larval Ascidian .... . . 235 



„ 86. Compound Ascidian ... . . 236 



„ 86. Balanoglossus ....... 238 



„ 87. Branchial Skeleton of a Fish, and its representa- 

 tive in an Amphibian and a Fowl . . . 246 

 „ 88. Section of Human Brain . . . . 246 



89. A Shark 



90. Egg of a Dog-fish 



91. Teeth of Skate . 



92. Development of Teeth of Newt 



252 

 253 

 254 

 255 



