FISH-LIVERIES, AND WHY THEY ARE WORN. 73 



of some carnivorous species, and so soon as he 

 is chased rushes back and plunges headlong down 

 the mouth of his kindly host. This brings his 

 would-be captor within reach of the tentacles 

 and paralysing stinging threads of the anemone, 

 from which there is no escape. The fish and the 

 anemone apparently then share the spoil ! 



We have seen that the colours of fishes may 

 become more brilliant during the season of court- 

 ship ; and we may now turn to the consideration 

 of some cases in which the colouration may under- 

 go sudden changes in brilliancy during periods 

 of excitement; much as we ourselves turn colour 

 from a deathly white to scarlet when possessed 

 by some sudden emotion. But the methods in 

 which these changes are made differ very much 

 in ourselves and in the fish. With us the sudden 

 change to scarlet is due to an increased supply 

 of blood to the face ; its sudden or complete 

 withdrawal causes pallor. With the fish, change 

 of colour to begin with is not necessarily from 

 red to white, or vice versd, but varies as the 

 colour of the fish. Furthermore, as we have 

 already hinted, the change is not connected with 

 the blood-supply, but with the deeper layer of 

 the skin and the colouring matter contained 

 therein. And in this fact we have a point of 

 exceeding interest, for this colouring matter is 

 contained within certain little bag-like structures, 

 whose form can be suddenly changed from a 

 globe to a disc by means of the contraction of 

 numerous little strands of muscular fibres at- 

 tached to the outside of the bag. Now, when 

 these little bags of colour, which are scientifically 



