SHALLOW-WATER FAUNA OF THE TROPICS. 73 



growing edge of the Coral-reef is carpeted with 

 Corals, Sponges and many other forms of animal 

 life ; in the water swim countless Fish, and the 

 branches of the Corals yield to the naturalist 

 innumerable forms of creeping and crawling 

 creatures. The shallow waters of the Tropics, 

 as a whole, however, do not possess a parti- 

 cularly rich Fauna, in fact, the distinguished 

 Dr Kukenthal, who has had great experience of 

 marine work, says that, in his opinion, the 

 Tropical seas are not richer in littoral animals 

 than the Arctic seas. Between the reef and the 

 sea-beach there is a lagoon, of varying breadth, 

 with a sandy bottom, which is almost as barren 

 of animal life as a desert. A few Worms and 

 Crabs, here and there a Star-fish and some shells 

 of Foraminif ers, are all the spoils which fall to the 

 bag of the naturalist after many hours' wading 

 on this unprofitable ground. The reason for this 

 is, perhaps, not far to seek. When the tide goes 

 down many stretches of sand are left dry, and 

 others retain only a few inches of water. The 

 exposure to the heat of a Tropical sun soon kills 

 and dries up any living animal that is unable to 

 burrow deeply in the sand, and the water in the 

 shallow pools rises in temperature to a degree 

 that the human hand or foot can only just bear, 

 so that the little Fish that escape into them run 

 the risk of being slowly cooked alive. 



On the inside of the lagoon there is, in many 

 places, a broad belt of Mangrove trees, forming 

 the " Mangrove-swamp," which contains some in- 

 teresting and important animals. These trees 

 have a peculiar spreading and branching system 



