CCELENTERATA. 1 8? 



resembling the adult is formed as a bud. The bud becomes 

 detached and then gives rise to a permanent sexual Fungia. 

 From the nurse-stock there is formed however a fresh bud at 

 the centre of the scar left on the detachment of the old one. 

 The fresh bud eventually becomes separated from the nurse-stock 

 leaving a small portion of its stem behind ; each succeeding bud 

 similarly leaves a small portion of its stem, so that the nurse- 

 stock eventually acquires a jointed appearance. In the above 

 process we clearly have, as in the Hydromedusae, a non-sexual 

 form the nurse-stock produced directly from the larva, giving 

 rise by budding to a sexual form ; all the conditions of an alter- 

 nation of generations are therefore fulfilled. It seems however 

 possible that the nurse-stock itself may eventually become sexual. 



BIBLIOGRAPHY. 

 Ccelenterata. General. 



(145) Alex. Agassiz. Illustrated Catalogue of the Museum of Comparative 

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(146) O. and R. Hertwig. Der Organismus d. Medusa: u. seine Stelltmg z. 

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(147) A. Kowalevsky. "Untersuchimgen lib. d. Entwicklung d. Ccelente- 

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 d. Anat. u. Phys. (Hoffman u. Schwalbe), 1873. 



Hydrozoa. 



(148) L. Agassiz. Contributions to the Natural History of the United States of 

 America. Boston, 1862. Vol. IV. 



(149) G. J. Allman. A Monograph of the Gymnoblastic or Tubularian Hydroids. 

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(150) G. J. Allman. "On the structure and development of Myriothela." Phil. 

 Trans., Vol. CLXV. p. 2. 



(151) P. J. van Beneden. "Mem. sur les Campanulaires de la Cote d'Ostende 

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 Mem. de FAcad. de Britx., Tom. xvn. 1844. 



(152) P. J. van Beneden. " Recherches sur 1'Embryogenie des Tubulaires et 

 1'histoire naturelle des differents genres de cette famille qui habitent la Cote d'Ostende." 

 Nouv. Mem. de P Acad. de Brux., Tom. XVII. 1844. 



(153) C. Claus. "Polypen u. Quallen d. Adria." Denk. d. math.-naturwiss. 

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(154) J. G. Daly ell. Rare and Remarkable Animals of Scotland. London, 

 1847. 



(155) H. Fol. "Die erste Entwicklung d. Geryonideneies. " Jenaische Zeit- 

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(156) Carl Gegenbaur. Zur Lehre vom Generationswechsel und der Fort- 

 pflanzung bei Medusen und Polypen. Wilrzburg, 1854. 



