LIST OF ENGRAVINGS. xxiii 



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156 Dytiscus marginalis, upper side, (Roesel) . . . 2:37 



157 Lower side of the same insect, (id.) . . . 287 



158 Notonecta glauca, (Rccsel) . . . . . 238 

 158* Fore leg of Gryllotalpa, (Kidd) . . . 242 



159 Wing of Gryllus nasutus. Orthoptera . . . 246 

 1(S0 Wmg 0^ Lihellula grandis. Neuroptera . . 246 



161 Wing of Ichneumon persuasorius. Ilymenoptera . . 246 



162 Wing of Tipula oleracea. Diptera . . . 246 



163 Sting of Antliophora retusa, (original) . . . 248 



164 Separate scales of the wing oT Hesperia Sloanus, (original) 250 



165 Arrangement of the scales in the wing of the same . . 250 



172 Longitudinal section of the thigli-bone to show the cancel- 



lated structure, (Cheselden) .... 262 



173 Longitudinal section of the humerus, (id.) . . 262 



174 Ossification of the parietal bone, (id.) . . . 265 



175 Early stage of ossification of the bones of the skull, (Cloquet) 265 



176 The same in the adult, showing the sutures . . . 265 



177 Dorsal vertebra, human ..... 271 



178 Junction of vertebrse forming the spinal column . . 271 



179 Longitudinal section of the same, showing the spinal canal 271 



180 Elements of structure of a vertebra, (Cams) . . . 274 



181 Skeleton of Hog, (Pander and D'Alton) . . .279 



182 Sternum, clavicle, and scapula ; human . . . 279 



184 Skeleton of Cyprinus carpio, (Bonnaterre) . . 286 



185 Diagram illustrating the progressive motion of Fishes . 287 



186 Front view of the vertebra of a Cod, (Gadus morrhua) . ' 288 



187 Side view of the same ..... 288 



188 Vertical and longitudinal section of a part of the spinal co- 



lumn in the same ..... 288 



189 A similar section, showing the gradation of structure . 288 



190 Similar section in the Squalus centrina, (Carus) . . 288 



191 Bones 0^ the shoulder of the Lophius piscatorius, (id.) . 293 



192 Pectoral fin of the Raia davata, (id.) . . . 293 



193 Belt of bones of the shoulder of a Ray, (id.) . . 294 



194 Muscular system of Cyprinus alburnus, (id.) . . 295 



195 Air bladder of Cyprinus carpio, (Blasius) . . 298 



196 Eggs of the Frog . . , . . . ,303 



197 Side view of Tadpole magnified, (Rusconi) . . 303 



198 Upper view of the same, (id.) .... 303 



199 Adult Frog ' 303 



200 Skeleton of Frog, (Cheselden) .... 306 



201 Skeleton of the Viper ..... 310 



