LIST OF ILLUSTRATIONS 



XXI 



no. 

 82. Sycon gelatinoRum, pore-membrane 

 8:^. „ ,, apopyle . 



84. External form of variou.s Sponges . 



85. Ascetta primordialis 



80. Diagrams of canal system of various Spfinges 



87. Vertical Section of Spongilla . 



88. Cells of ectoderm of Sponge . 



89. Development of tri-radiate Spiculo 



90. Skeleton of various Sponges .... 



91. Various forms of Sponge Spicules 



92. Pheronema Carpenteri 



93. Larva of Clathrina blanca 



94. Development of Sycon raphanus 



95. Obelia .... 

 9tj. ,, Vertical section of polype 



97. Nematocysts of Hydra 



98. Tentacle of Eucopella 



99. Obelia, medusa . 



100. Diagram of medusa . 



101. Derivation of medusa from polype 



102. Projections of polype and medusa, 



103. Development of zoophyte 



104. Bougainvillea ramosa 



105. Various forms of Leptolinfe . 



106. Ceratella . 



107. Hydra 



108. Protohydra leuckartii 



109. Various forms of leptoline Medusae 



110. Diagram illustrating formation of sporosac by degeneration of 



medusa . . . 



111. Early development of Eucope 



112. Two Trachymedusfe , 



113. Two Narcomedusae 



114. JEginura, tentaculocyst 



115. Larva of ^ginopsis . 



116. Millepora alcicornis, skeleton 



117. Millepora, diagram of structure 



118. Stylaster sanguineus, skeleton 



119. Halistemma tergestinum 



120. Diagram of a Siphonophore 



121. Development of Halistemma . 



122. Physalia .... 



123. Diphyea campanulata 



124. Porpita Pacifica 



125. Graptolites 



126. Aurelia aurita, dorsal and ventral views 



127. ,, ,, side view and vertical section 



128. ,, ,, portion of umbrella with tentaculocyst 



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