III.] INDEPENDENT SIMILARITIES OF STRUCTURE. 87 



SO far from it, in his lecture on tliis subject at the Royal 

 Institution before referred to, he observes: • " I can testify, 

 from personal experience, it is possible to have a comj^lete 

 faith in the general doctrine of evolution, and yet to hesi- 

 tate in accepting the Nebular, or the Uniformitarian, or 

 the Darwinian hypotheses in all their integrity and ful- 

 ness." 



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

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

 witli an absolute and pure Darwinian. 



Yet stronger arguments of an analogous kind are, how- 

 ever, to l)e derived from the liighest organs of sense. In 

 the most perfectl3'-organized animals — tliosc, namel}', which, 

 Hkc ourselves, possess a spinal column — the internal organs 

 of hearing consist of two more or less complex membranous 

 sacs (containing calcareous particles — otoliths), which are 

 primitively or permanently lodged in two chambers, one on 

 each side of the cartilaginous skull. The primitive cartila- 

 ginous cranium supports and protects the base of the brain, 

 and the auditory nerves pass from the brain into the cartila- 

 ginous chambers to reach the auditory sacs. These com- 

 plex 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 was fully evolved at the time of the deposi- 

 tion of the upper Silurian rocks. 



Cuttlefishes ( Cephalopoda) are animals belonging to the 

 molluscous primary division of the animal kingdom, which 

 division contains animals formed upon a type of structure 

 utterly remote from that on which the animals of the 

 higher division provided with a spinal column are construct- 

 ed. And indeed no transitional form (tending even to 

 bridge over the chasm between these two groups) has ever 



9 <« P 



rroccedings of the Royal Institution," vol. v., p. 270. 



