LIST OF ILLUSTRATIONS. xiii 



FIG. FAGH 



67. Diagram of a typical Hydrozoon polyp after Allman . 141 



68. Hydra hanging from water- weed after Greene . 143 



69. Minute structure of Hydra after T. J. Parker and Jickeli . 145 



70. Development of Hydra after Brauer . . .148 



71. Bougainvillea after Allman . . . .150 



72. Structure of a Medusoid after Allman . . 151 



73. Surface view of Aurelia from Romanes . . . 153 



74. Vertical section of Aurelia after Glaus . . . 155 



75. Diagram of life history of Aurelia after Haeck el . .156 



76. Lticernaria after Korotneff . . . .158 



77. Diagram of Lucernaria after Allman . . ,158 



78. External appearance of Tealia crassicornis . . 160 



79. Vertical section of a sea-anemone after Andres . .161 



80. Section through sea-anemone (across arrow in Figure 79) 



after Andres . . . . . .162 



81. Z, Diagrammatic section of Zoantharian ; A, of Alcyonarian 



after Chun . . . . .163 



82. The formation of a coral shell (Astroides) after Pfurtscheller 165 



83. Structure of Antipatharians ..... 166 



84. Diagrams of Types of Alcyonaria after Hickson . . 167 



85. Coral Hum rubrum, a corner of a colony after Lacaze- 



Duthiers . . . . . .168 



86. Alcyonarian Spicules . . . . .169 



87. Diagram of a gymnoblastic Hydroid after Allman . ,170 



88. Graptolites . . . . . . .171 



89. Hydroids after Hincks . . . . .172 



90. Campanularian Hydroid after Allman . . -173 



91. Diagram of a Ctenophore after Chun . . . 174 



92. Hydroctena. A medusoid with hints of Ctenophore structure 175 



93. Commensalism of sea-anemones and hermit-crab . . 177 

 Q3A. Portions of excretory system of flat-worms , . 178 



94. Diagram of Turbellarian after Lang . . .181 



95. Structure of liver fluke after Sommer. From ventral surface. 



The branched gut (g.} arid the lateral nerve (/..) are 

 shown to the left, the branches of the excretory vessel 

 (e.v.) to the right . . . . .184 



96. Reproductive organs of liver fluke after Sommer . .185 



97. Life history of liver fluke after Thomas . . . 187 



98. Diagram of life cycle of liver fluke . . . .189 



99. Diagram of reproductive organs in Cestode joint Constructed 



from Leuckart . . . . .- .192 



100. Life history of Tcenia solium after Leuckart . 193 



101. Diagram of life history of Tcenia solium . . . 194 



1 02. Diagrams of bladder- worms . . . . .196 



103. Diagrammatic longitudinal section of a Nemertean (Amphi- 



porus lactifloretis}, dorsal view after M'Intosh . 197 



104. Transverse section of the Nemertean Drepanophorus latus 



after Burger . . . . . .198 



105. Transverse section of a simple Nemertean (Carinella) after 



Burger . , . . , . .199 



