XVI THE MICROSCOPE. 



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137. Oosmariunt , conjugating 57 



138. Epithemia gibba, conjugating 43 



139. Melosira nummuloides, conjugating 59 



140. Transverse section of common sponge 68 



141. Transverse section of common British sponge .... 69 



a. Spicules of the same more magnified. 



Calcareous spicules of Grantia ciliata. 68 



142. Pin-like spiculum from Cliona, a boring sponge . . 69 



143. Spiculum from Spongilla, a fresh-water sponge . . 69 



144. Spiculum from unknown sponge 69 



145. Spiculum from Tethea 39 



146. Common Hydra 70 



a. Stinging organ from common Hydra 



147. A species of Sertularia, a zoophyte 71 



148. Campanularia integra, a zoophyte 71 



149. " Cup" of Campanularia volubilis, a zoophyte. ... 71 



150. Spicula of Gorgonia verrucosa 71 



151. Transverse section from base of spine of Echinus 



neglectus 72 



152. Calcareous rosette from sucker of Echinus .... 72 



153. Pedicellaria from Echinus 72 



154. Pedicellaria from star-fish ,, 72 



PLATE VI. to face page 72. 



155. Lepralia, a polyzoon 72 



156. Eowerbarikia densa, a polyzoon 73 



157. Tobacco-pipe, or bird's-head processes of Notamia 73 



a. Bird's-heau process. 



158. Bugula avicularia 73 



159. Bird's-head process of Bugula Murrayana . .. 73 



