I] 
THE EARLIEST KNOWN VERTEBRATES 
“We are the ancients of the earth 
And in the morning of the times.” 
There is a universal, and perfectly natural, de- 
sire for information, which in ourselves we term 
thirst for knowledge and in others call curiosity, 
that makes mankind desire to know how every- 
thing began and causes much speculation as to 
how it all willend. This may take the form 
of a wish to know how a millionaire made his 
first ten cents, or it may lead to the questions 
—W hat is the oldest animal? or, What is the 
first known member of the great group of back- 
boned animals at whose head man has placed 
himself? and, What did this, our primeval and 
many-times-removed ancestor, look like? The 
question is one that has ever been full of inter- 
est for naturalists, and Nature has been inter- 
rogated in various ways in the hope that she 
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