LIST OF ILLUSTRATIONS 



FIG. PAGE 



1 1 8 Crayfish, transverse section 



of thorax .... 224 



119 ,, diagram of circula- 



tion 225 



1 20 ,, nervous system . 227 



121 ,, reproductive organs 228 



122 Crab 230 



123 Hermit-Crab 231 



124 Apus 232 



125 ,, development . . . 233 



126 Cyclops and Calocalanus . 234 



127 Barnacle 235 



128 Peripatus 236 



129 ,, head 237 



130 ,, anatomy . . . 238 



131 Cockroach, lateral view of 



head . . . 240 



132 ,, mouth-parts . 241 



133 Butterfly 242 



134 Beetle ..'....... 243 



135 Mosquito 244 



136 Cockroach, anatomy . . 245 



137 tracheal system 246 



138 ,, nervous system 247 



139 Centipede 252 



140 Scorpion, dorsal view . . 254 



141 ,, ventral view . 255 



142 anatomy . . . 257 



143 Spider ........ 258 



144 Itch mite . 259 



145 Limulus 260 



146 Fresh-water mussel . . . 265 



147 ,, interior of valve 



and animal re- 

 moved from shell 267 



148 ., section of shell 



and mantle . 268 



149 ,, after removal of 



left mantle 

 lobe 269 



150 ,, dissection ... 271 



FIG. PAGE 



151 Fresh- water mussel, struc- 



ture of gills ... . 273 



152 ,, diagram of cir- 

 culation 275 



153 ,, embryo ... 277 



154 Mytilus 278 



155 Teredo 279 



156 Chiton, dorsal view ... 281 

 J 57 ventral view . . 282 



158 ,, nephridial and 



genital systems 283 



159 Helix 28 j. 



1 60 Shell of Triton 285 



161 ,, longitudinal 



section .... 286 



162 Shell of Solarium . . . 287 



163 Shell of Terebra .... 288 



164 Cyprsea 289 



165 Doris 289 



1 66 Pteropoda 291 



167 Patella 292 



168 Slug, pulmonary cavity and 



related parts 293 



169 Triton, section of buccal 



cavity 294 



170 Cuttle-fish . 297 



171 Nautilus, female, in shell . 298 



172 ,, section of shell . 299 



173 Spirula 300 



174 Cuttle-fish, shell .... 301 



175 Squid 302 



176 Argonauta, shell .... 303 



177 Cuttlefish, chromato- 



phores 303 



178 ,, dissection of 

 female 304. 



179 Nautilus, mantle-cavity of 



male 305 



1 80 Cuttle-fish, jaws .... 306 



181 ,, enteric canal . 307 



182 Balanoglossus 310 



