LIST OF ILLUSTRATIONS 



FIG. PAGE 



106. Nereis dumerilii, natural size . . . 189 



107. Nereis dumerilii, parapodium . ... 190 



10S. Nereis dumerilii, setje ........ 191 



109. Nereis dumerilii, anatomy .... . . 192 



no. Nereis dumerilii, transverse section . . . . 194 



in. Section through the eye of Nereis . 196 



112. Brain and connecting nerves of Nereis . . . 197 



113. Serpuke in their tubes . . . . 198 



114. Trochosphere of Eupomatus . . . 199 



115. Lumbricus agricola .... . 200 



116. Lumbricus, setee .... . 201 



117. Hirudo medicinalis . . . 204 



118. Head of Hirudo medicinalis, showing the thrre jaws . . 205 



119. Head of Hirudo quinquestriata . . 206 



120. Nephridium of the medicinal leech 208 



121. Transverse section of Hirudo . . . 209 



122. Diagram of blood-channels of leech ..... 210 



123. Astacus fluviatilis .... . 214 



124. Appendages of Astacus . .... 217 



125. Astacus fluviatilis, dissection from right side . . 221 



126. Respiratory organs of Astacus fluviatilis . . . 223 



127. Thorax of crayfish, transverse section . 225 



128. Diagram of the circulation in the crayfish . . 226 



129. Nervous system of Astacus fluviatilis . .. 227 



130. Reproductive organs of Astacus fluviatilis . . 229 



131. Cancer pagurus .... . 230 



132. Pagurus bernhardus ... . . 231 



133. Apus glacialis ..... . . 232 



134. Development of Apus . 233 



135. Cyclops and Calocalanus ... . 234 



136. Lepas anatifera . . . 235 



137. Peripatus capensis . . 237 



138. Peripatus capensis, head, etc. . 237 



139. Internal organs of Peripatus . 238 



140. Scolopendra . . . 240 



141. Periplaneta americana . . . 242 



142. Mouth-parts of the cockroach . 243 



143. Pieris rap^e, larva, and pupa .... . 244 



