III.] IXDEPEXBEXT SIMILARITIES OF STRUCTURE. 83 



against the specially Darwinian form of it. Kow this 

 form lias never been expressly adopted by Professor 

 Huxley ; so far from it, in his lecture at the Eoyal 

 Institution before referred to, he observes/ " I can testify, 

 from personal experience, it is possible to have a complete 

 faith in the general doctrine of evolution, and yet to 

 hesitate in accepting the Nebular, or the Uniformitarian, 

 or the Darwinian hypotheses in all their integrity and 

 fulness." 



It is quite consistent, then, in the Professor to explain 

 the difficulty as he does ; but it would not be similarly so 

 with an absolute and pure Darwinian. 



Yet stronger arguments of an analogous kind are, how- 

 ever, to be derived from the highest organs of sense. In 

 the most perfectly organized animals — those namely which, 

 like ourselves, possess a spinal column — the internal organs 

 of hearing consist of two more or less complex mem- 

 branous sacs (containing calcareous particles— otoliths), 

 which are primitively or permanently lodged in two cham- 

 bers, one on each side of the cartilaginous skull. The 

 primitive cartilaginous cranium supports and protects the 

 base of the brain, and the auditory nerves pass from that 

 brain into the cartilaginous chambers to reach the auditory 

 sacs. These complex arrangements of parts could not 

 have been evolved by "Natural Selection," i.e. by minute 

 accidental variations, except by the action of such through 

 a vast period of time ; nevertheless, it w^as fully evolved 

 at the time of deposition of the Upper Silurian rocks. 



Cuttle-fishes {Ceijhaloiooda) are animals belonging to the 

 molluscous primary division of the animal kingdom, which 

 division contains animals formed upon a type of structure 



^ " Prooeeilkigs of the Eoyal Institution," vol. v. p. 279. 



G 2 



