DESCRIPTION OF PLATES. XI 



FIG. PAGE. 



137. Melosira nummuloides, conjugating 41 



138. Transverse section of common sponge 50 



139. Transverse section of common British sponge .... 50 



140. Pin-like spiculum from Cliona, a boring sponge . . 50 



141. Spiculum from Spongilla 50 



142. Spiculum from Tetkea 51 



143. Spiculum from unknown sponge 51 



144. Common Hydra 52 



a. Stinging organ from common Hydra. 



145. A species of Sertularia, a zoophyte 52 



146. Campanularia Integra, a zoophyte 52 



147. " Cup " of O. volubilis, a zoophyte 53 



148. Spicula from Gorgonia, a zoophyte 53 



149. Transverse section from base of spine of Echinus 



limdus 53 



150. Calcareous rosette from sucker of Echinus 53 



151. Pedicellaria from Echinus '. 53 



152. Pedicellaria from star-fish 53 



PLATE VI. 



153. Lepralia pallasiana, a polyzoon 54 



154. Bowerbankia densa, a polyzoon 54 



155. Tobacco-pipe, or bird's-head processes of No- 



tamia 54 



156. Bugula avicularia, with both bird's-head processes 



(avicularia) and sweeping bristles (vibracula) . 54 



157. Snake-headed zoophyte Anguinaria 55 



158. Flustra foliacea sea mat 53 



159. Plumatella repens, a fresh-water polyzoon 54-55 



160. Egg of Cristatella Mucedo, a fresh-water polyzoon 55 



