62 



SEASIDE DIVINITY. 



An examination of the eyes of a trilobite proves 

 that they were constructed in the manner now 

 described. The creature has two compound eyes, 

 each of them possessing several hundreds of the 

 separate visual organs already described, but each 

 imperfect on the side opposite to each other, be- 

 cause in that position unnecessary. Dr. Buckland 

 thus expresses himself on the subject : " We find 

 in the trilobite of those early rocks, the same modi- 

 fications of the organ of sight as in the living 

 crustaceans. The same kind of instrument was 

 also employed in the intermediate periods of our 

 geological history, when the secondary strata were 

 deposited at the bottom of a sea inhabited by 

 Limuli in those regions of Europe which now form 

 the elevated plains of Central Germany. But these 

 results are not confined to physiology : they prove 

 also, the ancient condition of the seas and the 

 atmosphere, and the relation of both these media 

 to light. For in those remote epochs the marine 

 animals are furnished with instruments of vision 

 in which the minute optical adaptations were the 

 same as those which now impart the perception of 

 light to the living Crustacea. The mutual relations 

 of light to the eye and of the eye to light were 

 therefore the same at the time when crustaceans 

 first existed at the bottom of the Silurian seas as 

 at the present moment." The conclusion at which 

 Dr. Buckland thus arrives may be less generally 

 expressed thus : At that period in the history of 

 the planet we inhabit, when its waters alone con- 

 tained living beings, countless ages before the 



