CHAPTER VIII 

 Colour and Phosphorescence 



In this short chapter we shall consider two of the most 

 interesting properties of marine animals, their colour 

 and the strange power, which many of them possess, of 

 producing light so that they appear phosphorescent at 

 night. Though colour and phosphorescence are not directly 

 connected they have this at least in common, that the 

 production of the former is greatly influenced by light 

 whereas the latter is concerned with the production of 

 light. 



Colour 



In the sea there are animals with as great a wealth and 

 variety of colour as any that are found on land. This 

 is a fact which people who live in temperate climes are 

 liable to overlook because our fishes have none of the 

 brilliancy of colour of those from tropic waters, while 

 the most beautiful of our marine creatures are anemones 

 which often lie concealed in rock pools or contracted on 

 the sides of rocks while the tide is out, or else small shrimps 

 and sea slugs which are known only to the naturalist with 

 the knowledge and enthusiasm to search for them. 



The remarkable property of colour change — whereby 

 an animal can change its colour to a greater or less extent, 

 usually in order to tone with its background for the time 

 being — is possessed by a far greater number of marine 

 than terrestrial animals. It is especially well developed 



179 N 



