LIST OF ILLUSTRATIONS xix 



FIG. PAGE 



68. Distomum hepaticum, natural size 130 



69. Distomum hepaticum, anatomy 131 



70. Distomum hepaticum, development 135 



71. Trematodes : Amphistomum and Homalogaster . . . 136 



72. Structure of a triclad turbellarian 137 



73. Planaria polychroa 138 



74. Taenia solium 139 



75. Taenia solium, head magnified 140 



76. Taenia solium, proglottis . 141 



77. Development of tape-worm 142 



78. Cyst of Taenia echinococcus with daughter-cyst and scolices 144 



79. Diagram of organs of a Nemertine ..... 146 



80. Tetrastemma, structure - . 147 



81. Ascaris lumbricoides .- . . . . . . 150 



82. Ascaris lumbricoides, dissection of female . . . . 151 



83. Diagram of nervous system of Nematoda .... 152 



84. Ascaris lumbricoides, posterior end of male dissected . . 153 



85. Trichina spiralis . . . . . . . . 155 



86. Starfish, showing tube feet .158 



87. Starfish, vertical section through an arm . . . .161 



88. Starfish, diagrammatic sections . . . . ... 164 



89. Asterias rubens, digestive system 165 



90. Ambulacral systems of a starfish .166 



91. Anthenea, dorsal surface 167 



92. Anthenea, ventral surface . . . . . . .168 



93. Ophioglypha lacertosa 169 



94. Strongylocentrotus 171 



95. Corona of sea-urchin 172 



96. Apical systems of plates of sea-urchin 172 



97. Cucumaria planci 174 



98. Antedon . . . 175 



99. Metacrinus interruptus 177 



100. Brachionus rubens 179 



101. Bugula avicularia 182 



102. Plumatella 183 



103. Pedicellina 184 



104. Magellania flavescens 185 



105. Magellania lenticularis, sagittal section .... 186 



