INTRODUCTION 5 
respect for local varieties has caused that veteran ichthyologist 
unduly to multiply species. But I have kept the purely 
scientific part of the history as subordinate as possible, retaining 
the classification merely as a clue, avoiding anatomical details, 
which I am wholly unable to give from original research, 
and merely indicating the number of fin-rays in each fish, and 
the arrangement of the teeth, as a simple aid to identification. 
Regarding the illustrations, I desire to acknowledge with 
gratitude the help I have received from those, too numerous 
to mention by name, who have kindly sent photographs for 
reproduction. One great difficulty has had to be encountered 
by Miss Seth, the artist who has prepared coloured reproductions 
of these photographs—namely, the rapid changes which take 
place in nearly all fish immediately after death. For instance, 
in almost every coloured representation that I have ever seen, 
the iris is coloured red or orange. Now the iris of a living or 
freshly killed salmon is the palest yellow, dusted with black ; 
it is only when:decomposition has begun that the eye becomes 
shot with blood; and the portrait of a salmon can seldom be 
taken until that process has set in. The delicate skin tints of 
trout, minnows, sticklebacks, and many other fish are equally 
evanescent, and tax to the utmost the artist’s ingenuity and 
rapidity of execution. 
