176 Thomas Huxley, Esq., on Animal Individuality. 



There is no such thing as a true case of the " Alternation 

 of Generations'' in the animal kingdom ; there is only an 

 alternation of true generation with the totally distinct pro- 

 cess of Gemmation or Fission. 



It is indeed maintained that the latter processes are equi- 

 valent to the former ; that the result of Gemmation as much 

 constitutes an individual, as the result of true Generation ; 

 but in that case the tentacles of a Hydra, the gemmiferous 

 tube of a Salpa, nay, the legs of a Centipede or Lobster must 

 be called individuals. 



And if it be said that the bud must have in addition the 

 power of existing independently, to constitute an individual ; 

 there is the case of the male Argonaut, which has been just 

 shewn by H. Muller to have the power of detaching one of 

 its arms (a result of gemmation) which then leads a separate 

 existence as the Hectocotylus. 



Without a misuse of words, however, no one would call 

 this a separate individual. 



In conclusion the lecturer stated his own views thus : 



The individual animal is the sum of the phenomena pre- 

 sented by a single life : in other words, it is, all those animal 

 forms which proceed from a single egg, taken together. 



The individual is represented in very various modes in the 

 Animal Kingdom : these modes pass insensibly one into the 

 other, in nature ; but for purposes of clear comprehension 

 they may be thus distinguished and tabulated. 



Representation of the Individual. 



I. By Successive Inseparable Forms. 



Ascaris. A. Forms little different = Growth. 



Triton. B. Forms markedly different = Metamorphosis. 



II. By Successive Separable Forms. 



1. Earlier Forms not Independent. 

 Cockroach. A. Forms little different = Growth with Ecdysis. 

 Beetle. B. Forms markedly different = Growth with Me- 

 tamorphosis. 



2. Earlier Forms partially Independent. 

 Starfish. 



