VIII. 
LATITUDE AND VERTEBRA. 
A STUDY IN THE EVOLUTION OF FISHES. 
In this paper is given an account of a curious bio- 
logical problem and of the progress which has been made 
toward its solution. The discussion may have a certain 
popular interest from the fact that it is a type of many 
problems in the structure and distribution of animals 
and plants which seem to be associated with the laws of 
evolution. In the light of these laws they may be more 
or less perfectly solved. On any other hypothesis than 
that of the derivation of species the solution of the 
present problem, for example, would be impossible. On 
the hypothesis of special creation a solution would be 
not only impossible but inconceivable. 
It has been known for some years that in several 
groups of fishes (wrasse fishes, flounders, and “rock 
cod,” for example) those species which 
inhabit northern waters have more ver- 
tebre than those living in the tropics. 
Certain arctic flounders, for example, 
have sixty vertebra; tropical flounders have, on the 
average, thirty. The significance of this fact is the 
problem at issue. In science it is assumed that all facts 
have significance, else they would not exist. It becomes 
necessary, then, to find out first just what the facts are 
in this regard. 
Northern fishes 
have most 
vertebre, 
221 
