PIGMENTS AND COLOURS 497 



fishes; for example, the butterfly-fish Heniochus acuminatus (Fig. 11.11) 

 and the common cuttlefish Sepia officinalis (Fig. 11.12). 



Warning coloration is another device widely utilized in association with 

 noxious or poisonous properties. Brightly coloured sponges, chromodorids 

 and stinging actinians are alike repellent to fishes, and an association is 

 quickly formed in possible predatory fish between the characteristic colour 

 and form of these animals and their noxious properties. Another highly 



Fig. 11.10. Alterations in Colour Pattern of the 

 Nassau Grouper Epinephelus striatus 



{Upper right) a phase in which the fish is dark above with light underparts. {Lower 

 right) a phase in which the whole body becomes darkly banded. {Middle left) another 

 phase in which the upper parts are sharply banded, with white underparts. (After 

 Townsend (79).) 



distasteful animal is the terebellid Polycirrus caliendrum. This worm is 

 bright red in colour, is very conspicuous and has been shown by Garstang 

 to be rejected by fish. Some animals have special warning markings in 

 association with poisonous properties. Conspicuous nudibranchs, such as 

 Eubranchus tricolor, have brightly coloured defensive papillae armed with 

 batteries of nematocysts. Many of the puffer fishes (Tetraodontidae) possess 

 poisonous flesh and are brightly coloured. The notorious weaver-fish 

 Trachinus vipera has poisonous glands associated with specially modified 



