xiv LIST OF ILLUSTRATIONS. 



KK;. 



119. Apical disc of sea-urchin ....... 250 



120. Diagram of sea-urchin (Echinus] (Huxley) . . . .251 



121. Dissection of Holothurian (Holothitria tubiilosa) from the 



ventral surface . . . . . . . .257 



122. Diagrammatic vertical section through disc and base of one 



of the arms of Antcdon rosacea (Milnes Marshall) . . 259 



123. Stages in development of Echinoderms (Selenka) . . 261 



124. Appendages of Norway lobster . . . . . .271 



125. Section of compound eye of Mysis vitlgaris (Grenacher) . 272 



126. A single eye element or ommatidium of the lobster (Parker) 273 



127. Longitudinal section of lobster, showing some of the organs 274 



128. Male reproductive organs of crayfish (Huxley) . . . 277 



129. Female reproductive organs of crayfish (Suckow) . . 278 



130. Section through the egg of Asfacns after the completion of 



segmentation (Reichenbach) 279 



131. Longitudinal section of later embryo of Astaczis (Reichenbach) 280 



132. Embryo of crayfish, flattened out, with removal of yolk 



(Reichenbach) ........ 281 



133. Dorsal aspect of swimming crab (Portitn us] . . . 283 



134. Dorsal aspect of shore crab ...... 283 



135. Ventral aspect of female shore crab ..... 284 



136. Dorsal surface of Apits cancriformis (from Bronn's 



"Thierreich") . .... 285 



137. Acorn-shell (Balamis tintinnabuluni) (Darwin) . . . 288 



138. Development of Saccnlina (Delage) ..... 289 



139. An Amphipod (Caprella linearis) ..... 292 



140. Hermit-crab withdrawn from its shell ..... 293 



141. Hermit-crab (Pagurns] in shell of Fitsus .... 294 



142. Schizopod (Mysis flexuosa) ...... 295 



143. Nervous system of shore crab (Cariinits uii?nas] (Bethe) . 296 



144. Zoaea of common shore crab (Carcinus intends) (Faxon) . 299 



145. External form of Peripatus (Balfour) ..... 303 



146. Dissection of Peripatus (Balfour) 305 



147. Embryos of Peripatus cape >i sis, showing closure of blasto- 



pore and curvature of embryo ( Korschelt and Heider) . 306 



148. A millipede .... .... 308 



149. A centipede ... ..... 308 



150. Female cockroach (P. orientalis] 310 



151. Male cockroach (P. oriental} s) 310 



152. Ventral aspect of male cockroach with the wings extended . 312 



153. Leg of cockroach ........ 313 



154. Mouth appendages of cockroach (Dufour) .... 313 



155. Transverse section of insect (Packard) .... 314 



156. Head and mouth-parts of bee (Cheshire) .... 317 



157. Nervous system of bee (Cheshire) ..... 319 



158. Food canal of bee (in part after Cheshire) .... 320 



159. Hive-bees and cells . . . . . . . .321 



1 60. One of theThysanura (Cainpodea staphy linns) (Lubbock) . 322 



161. Mouth-parts of Mosquito 324 



162. Young may-fly or ephemerid (Eaton) ..... 325 



