113. Three cases of mimicry 328

114. Two further cases of mimicry; flies resembling a wasp in the
one and a bee in the other 329

115. A case of mimicry where a non-venomous species of snake
resembles a venomous one 330

116. A case of mimicry where a homopterous resembles a leaf-cutting
ant 332

117. Feather-footed pigeon 359

118. _Raia radiata_ 368

119. Electric organ of the Skate 369

120. Electric cells of _Raia radiata_ 370

121. The Garden Bower-bird (_Amblyornis inornata_) 382

122. Courtship of Spiders 388

123. Courtship of Spiders (_continued_) 389

124. The Bell-bird (_Chasmorhynchus niveus_) 396

125. _C. tricarunculatus_ 397

SECTION I

_EVOLUTION_

CHAPTER I.

INTRODUCTORY.

Among the many and unprecedented changes that have been wrought by Mr.
Darwin's work on the _Origin of Species_, there is one which, although
second in importance to no other, has not received the attention which
it deserves. I allude to the profound modification which that work has
produced on the ideas of naturalists with regard to method.

Having had occasion of late years somewhat closely to follow the history
of biological science, I have everywhere observed that progress is not
so much marked by the march of discovery _per se_, as by the altered
views of method which the march has involved. If we except what
Aristotle called "the first start" in himself, I think one may fairly
say that from the rejuvenescence of biology in the sixteenth century to
the stage of growth which it has now reached in the nineteenth, there is
a direct proportion to be found between the value of work done and the
degree in which the worker has thereby advanced the true conception of
scientific working. Of course, up to a certain point, it is notorious
that the revolt against the purely "subjective methods" in the sixteenth
century revived the spirit of _inductive_ research as this had been left
by the Greeks; but even