MIMICRY 55 
these have a special interest for us, because they illus- 
trate the way in which the zeal of the seeker after adap- 
tive contrivances may run away with him if not kept 
wellin hand. For there is scarcely any limit to the num- 
ber of problematical cases which have been described 
as adaptive resemblances, and so explained as having 
arisen through natural selection, whilst the evidence 
in favour of such a supposition is in many cases highly 
questionable. On the other hand, in a number of 
well-marked instances, the theory of mimicry certainly 
seems to afford an adequate explanation of the way 
in which many curious characters and structures may 
possibly have come into existence. 
The families of the Mantidg and Phasmida, includ- 
ing the walking-stick and leaf insects, afford many 
examples of animals which both in their colour and 
configuration show a very close resemblance to sur- 
rounding inanimate objects. This resemblance must 
have the effect of concealing them from their enemies, 
and more particularly from their prey, as, indeed, a 
study of their habits indicates quite clearly. 
Phyllopteryx, an ‘Australian fish allied to the well- 
known sea-horse (Hippocampus), is provided with a 
number of irregular appendages of ragged skin 
resembling the seaweed amongst which this animal 
is found. In this way the characteristic symmetrical 
appearance of a live animal is got rid of, and the 
creature is rendered extremely difficult of observation. 
Here, again, the concealment afforded is probably 
useful in leading to the deception of the smaller 
organisms upon which the creature feeds. 
