( 53! J 



ron ne songeat pas encore a cetle epoque a rechorchcr 



I 



g 



ricurs, Huxley comprit toule la portee de sa decouveite. 

 II rcconnut et formula dans un langage clair et precis son 

 opinion sur riiomologie qu'il croyait exister eiilre reclo- 

 derme et rcndodcrmc dcs Ccelentercs et les deux feuillets 



cellulaires primordiaux des vertebres. 

 Voici en quels termes il cxpriraa cetteidL^e : 



< The peculiarity in the structure of tlie body-walls of 

 the Ilydrozoa, to which I have just referred , possesses a 

 singular interest in its bearing upon the truth that there 

 is a certain similarity between the adult stales of the 

 lower animals and the embryonic conditions of higher 

 organisation. 



For it is well known that, in a very early state, the 

 germ, even of the highest animals is a more or less com- 

 plete sac, whose thin wall is divisible into two mem- 

 branes, an inner and an outer; the latter, turned towards 

 the external world; the former, in relation with the nutri- 

 tive liquid, the yelk. 



The various organs are produced by a process of 



budding from one, or olhcr, or both of these primary 

 layers of the germ. » 



11 cherclie meme a etablir un parallelisme, au point de 

 vue histogenique, entre Tectoderme dcs Zoophytes et le 

 feuillet externe de Tembryon des vertebres d'un cole, 



Linnean Society en 1847 et public dans les Proceedi>gs of the Huyal 

 Society en jmn 1810). 



La Tneiiie opinion se trouve generalisee et exposee plus compleleiuent 

 dans un travaU publie la menne annee, Memoir on the anatomy and 

 ofjlnmes of the Medusie. 



