SHALLOW-WATER FAUNA OF THE TROPICS. 61 



for example, there may be seen Madrepores with 

 bright violet growing-points to their branches, 

 orange or red Fan-corals, bright brick-red Sponges, 

 yellow Sarcophytums, emerald green Organ-pipe 

 Corals and dozens of other forms of animal life 

 in every imaginable colour. When seen from a 

 boat through two or three feet of water, these 

 portions of the reef look more like a beautifully 

 planted flower-bed than a mass of animals ; but 

 the simile is not a complete one, for the branches 

 of the Madrepores, the great knobs and lumps of 

 the Brain and Organ-pipe corals, the fronds of 

 the Gorgonias and other forms make a wild mass 

 of organisms resembling a tangled thicket or a 

 miniature forest. At low water of spring-tides 

 the living reef is partly left exposed, and then 

 the scene changes, for the Polyps retract their 

 tentacles after the manner of the Sea-anemones 

 and retreat as far as possible into the shelter 

 afforded by their shells. 



The interest of the living reefs is, however, by 

 no means confined to such organisms as the Corals 

 and Sponges, which are immoveably fixed to the 

 bottom ; for numerous brightly - coloured Star- 

 fishes, Sea-urchins, Brittle-stars, Sea-slugs, and 

 their allies crawl about among the branches and 

 the debris of the dead Corals ; while Crabs, Lob- 

 sters and Shrimps of many kinds may be seen 

 swimming or crawling in search of their prey, 

 and the marvellously striped and spotted Coral 

 fishes dart hither and thither in the thicket, or 

 remain hovering in the water among the Corals. 

 The whole scene is most fascinating. As the boat 

 slowly drifts along, new and strange creatures are 



