76 



HYDIIOZOA. 



both the free zooids of the Hydrozoa and the 

 organisms from which they sprung as alike en- 

 titled to the rank of individual beings, belonging 

 to allied groups, and mutually reproducing each 

 other by a process of "alternate generation." But 

 in addition to the more general objection which 

 may be raised against this hypothesis, confounding, 

 as it does, true generation with gemmation or 

 fission, the one, an act of reproduction, the other, 

 of development, it is sufficient to show that, in 

 the present instance, its application is based on 

 a very superficial examination of the facts to he 

 explained. The gradual series of transitional 

 homologous forms, so surely connecting the com- 

 plex free gonophores of certain Hydrozoa with 

 the simple reproductive processes of Hydra or 

 Hydractinia, could not have been very familiar 

 to the minds of those who would have hesitated, 

 if called upon, in accordance with Steenstrup's 

 theory, to impute individuality to the latter. 

 Professor K. Leuckart, however, consistently does 



this, 



and would regard as 



true individuals the 



independent polymorphic buds of the same com- 

 posite Hydrozoon. And Mr. Lubbock has justly 

 remarked that, "whether we retain the old nomen- 

 clature, or dropping the idea of unity in the term 

 € individual,' adopt the system proposed by Pro- 

 fessor Huxley, we shall be met by great difficulties 

 and inconsistencies." It behoves us, therefore, to 

 follow that explanation which embodies in the 

 simplest manner all the observed phenomena, and 

 which is, at the same time, least characterised by 

 inconsistency. 



Recently, Professor 



modification of Leuckart's 



Agassiz 



has 



sed a 



propo 

 theory, and suggests 





