544 THE UNIVERSE. 



The globe at that time supported nothing but a very 

 small number of sea-animals, belonging to classes of the 

 lowest order of organization, as if Nature, still feeble and 

 undecided, were in their production making the first trial of 

 her strength. 



The seas, still warm, occupied at this time nearly all the 

 surface of the globe, and only very small portions of land 

 had emerged from the waters, islets lost in the midst of 

 a boundless ocean. Crustaceans, a few scattered molluscs, 

 polypoids, and a small number of fish were the sole tenants 

 of the deep. 



But among the silurian animals, those which especially 

 predominated were the trilobites, the name of which is de- 

 rived from the arrangement of their articulated bodies, 

 formed, to a certain extent, by three long lobes ranged 

 side by side to each other. No living representative of 

 these crustaceans, which were the most ancient inhabitants 

 of the globe, is now found in our seas : they are absolutely 

 struck out of the catalogue of created beings. 1 



1 Although thousands, perhaps millions, of years separate us from the period 

 at which the trilobites existed, yet, by a fortunate accident, geologists have some- 

 times met with specimens so perfect that the delicate structure of the eyes could 

 be made out in them ; and it has been shown that these organs were constructed 

 upon exactly the same plan as those of the crustaceans which now inhabit our 

 seas. 



These revelations suffice to establish a parallel between the extreme points of 

 creation ; and hence Buckland, after an examination of this apparatus, daringly 

 painted the condition of the globe at the time when these strange crustaceans lent 

 life to it, " The results," he says, " arising from these facts are not confined to 

 animal physiology ; they give information also regarding the condition of the an- 

 cient sea and ancient atmosphere, and the relations of both these media to light, 

 at that remote period when the earliest marine animals were furnished with in- 

 struments of vision, in which the minute optical adaptations were the same that 



