PREFACE. -♦--
In writing this book about Crayfishes it has not
been my intention to compose a zoological mono¬ graph on that group of animals.
Such a work, to
be worthy of the name, would require the devotion of years of patient study to a mass of materials collected from many parts of the world.
Nor has
it been my ambition to write a treatise upon our English crayfish, which should in any way pro¬ voke comparison with the memorable labours of Lyonet, Bojanus, or Strauss Durckheim, upon the willow caterpillar, the tortoise, and the cockchafer. What I have had in view is a much humbler, though perhaps, in the present state of science, not less use¬ ful object.
I have desired, in fact, to show how
the careful study of one of the commonest and most insignificant of animals, leads us, step by step, from every-day knowledge to the widest generalizations
