124 COLOUR IN NATURE 



The Pigments of Crustacea 



I. The Lipochromes. — That the yellow, orange, 

 and red pigments of the Crustacea are lipochromes 

 was long since proved by the researches of Maly, 

 Krukenberg, and others. Further, the lipochromes 

 have been described as usually occurring in pairs — a 

 red and a yellow together, which can be separated by 

 the process of saponification. 



A superficial examination of the colours of 

 Nephrops norwegicus, the Norway lobster, shows that 

 the epidermis is bright red, and the shell orange-red, 

 the colour of a boiled lobster. If, however, the shell 

 be decalcified with dilute acid, it entirely loses its 

 orange colour and becomes dull red — the colour of 

 the epidermis. The interest of this change lies in 

 the fact that while the boiled lobster, and those parts 

 of the lobster's shell which are not blue during life, 

 are of a similar orange colour, the shells of deep-sea 

 Crustacea tend to show such colours as " blood-red " 

 " deep crimson," '' crimson-red," and so on, and are 

 usually not orange. Now the red lipochrome of the 

 lobster or crayfish when removed from the shell very 

 readily forms a combination with linje which is of 

 orange colour. The shells of the deep-sea Crustacea 

 contain little or no lime ; it therefore seems to me 

 possible that the difference in colour between, say, 

 Nephrops and one of the deep-sea Crustacea is not 

 due to any difference in pigment, but only to the fact 

 that in the former the lipochrome occurs associated 

 with lime, and in the latter in the pure state. This 

 is interesting, because Moseley during the voyage of 



