THE SILURIAN SYSTEM. 



673 



eyes of existing crustaceans would have been found in the organs on which the im- 

 pressions of such rays were then received. Regarding light itself, also, we learn, from 

 the resemblance of these most ancient organisations to existing eyes, that the mutual 

 relations of light to the eye, and of the eye to light, were the same at the time when 

 crustaceans, endowed with the faculty of vision, were first placed at the bottom of the 

 primeval seas, as at the present moment. Thus we find among the earliest organic 

 remains, an optical instrument of most curious construction, adapted to produce vision 

 of a peculiar kind in the then existing representatives of one great class in the articulated 

 division of the animal kingdom. We do not find this instrument passing onwards, as it 

 were, through a series of experimental changes, from more simple into more complex 

 forms : it was created, at the very first, in the fulness of perfect adaptation to the use 

 and condition of the class of creatures to which this kind of eye has ever been, and is 

 still, appropriate. If we should discover a microscope, or telescope, in the hand of an 

 Egyptian mummy, or beneath the ruins of Herculaneum, it would be impossible to deny, 

 that a knowledge of the principles of optics existed in the mind by which such an 

 instrument had been contrived. The same inference follows, but with cumulative force, 

 when we see nearly four hundred microscopic lenses set side by side in the compound 

 eye of a fossil trilobite ; and the weight of the argument is multiplied a thousand fold, 

 when we look to the infinite variety of adaptations by which similar instruments have 

 been modified, through endless genera and species, from the long-lost trilobites of the 

 transition strata, through the extinct crustaceans of the secondary and tertiary formations, 

 and thence onwards throughout existing crustaceans, and the countless hosts of living 

 insects. It appears impossible to resist the conclusions as to unity of design in a common 

 Author, which are thus attested by such cumulative evidences of Creative Intelligence 



