ILLUSTRATIONS xxi 



FIO. PAGE 



126. The formation of the appendages in the embryo of Peripatus c(tj>i:iisis . 175 



127. Two sections through the developing egg of Astacus . . 179 



128. Sagittal section through the blastula of Astacus fluviatilis in order to 



show the primary yolk pyramids ...... 180 



129. Ventral view of an embryo of Astacus fluviatilis, the gastrula stage, in 



order to show the ventral plate . . . . . .181 



130. Sagittal section through a portion of the embryo of Astacas fluviatilis in 



order to show the imagination of the endodermic rudiment . .182 



131. Two sagittal sections through developing eggs of Astacus fluviatilis in 



order to show the development of the endoderm .... 182 



132. The " Nauplius " stage in the development of Astacus fluviatilis, viewed 



from the ventral side . . . . . . .184 



133. Three transverse sections through the developing nerve cord of Astufux 



fluviatilis . . . . . . . . .185 



134. Two views of developing eggs of Astacus fluviatilis from the ventral surface 186 



135. Transverse section through the region of the heart in an embryo of 



Astacus fluviatilis in about the same stage as that represented in Fig. 



134 B ...... 187 



136. Longitudinal section through advanced embryo of Astacus fluviatilis 



parallel to the sagittal direction but to one side of the middle line . 187 



137. Advanced embryo of Astacus fluviatilis, viewed from the ventral side. The 



abdomen and hinder part of the thorax are cut off and spread out 

 separately ......... 188 



138. Two ommatidia from the eye of a newly-hatched Astacus fluviatilis in 



longitudinal section ....... 188 



139. Two sagittal sections through advanced embryos of Astacus fluviatilis . 190 



140. Portions of two sagittal sections through developing eggs of Homarus 



americanus ......... 191 



141. Sections through the developing egg of Mysis chamaeleo . . 192 



142. Stages in the development of the egg of Polyphemus pcdiculus . . 193 



143. Four sagittal sections through the developing eggs of Lepas anatifera in 



different stages of development ...... 195 



144. The Nauplius larva of Cyclops cantliocarnoidcs from the ventral surface . 197 



145. Three stages in the further development of the larva of Cyclops . . 198 



146. Two types of Nauplius larva ...... 199 



147. The " Cypris " larva or Pupa of Lepas fascicularis, seen from the wide . 200 



148. The fixation of the Cypris larva of Lepas fascicularis . 201 



149. The Nauplius larva of Cypris ovum, . . . 202 



150. The Protozoaea larva of Nyctiphancs australis 203 



151. Dorsal and ventral views of the " Copepodid " larva of Adheres ambloplitis 205 



152. Dorsal and lateral views of the just-fixed female of Adheres amblopltiis . 206 



153. Lateral view of female Adheres ambloplitis after the adult characteristics 



have been attained ..... 206 



154. Enlarged view of gnathites and lips of female Adheres aw/i/nfJit/s, seen 



from the side ..... 207 



155. " Calyptopis " Zoaea of Nydiphanes aiistralis, lateral view . 208 



156. Zoaea larva of Penacus, ventral view . . . 209 



157. Zoaea larva of Crane/on vulgaris, lateral view 



158. Zoaea larva of Porccllana longicornia after the lirst moult . 211 



159. Zoaea larva of the Crab Xantho 



160. " Mysis " larva of Homarus amcricanus, lateral view 



161. " Phyllosoma " larva of Palinurus vulgaris, ventral view . 214 

 :< Mysis " larva of Cranrjon allinauni, lateral view . 



