74 THE STORY OF LIFE IN THE SEAS. 



of roots which are left exposed when the tide 

 goes down, and form with one another a kind of 

 network or web a foot or more above the ground, 

 upon which it is possible, with care, to walk 

 from place to place, at low tide. Between the 

 roots there is a slimy black sand or ooze, some- 

 times hard enough to walk upon, but more 

 commonly soft and treacherous. At high tide 

 the water rises to a height of two or three 

 feet, completely covering the roots and giving 

 the swamp the appearance of a forest growing 

 in the sea. Of the animals, aerial and terres- 

 trial, that haunt the swamps it is not necessary 



FIG. 24. Periophthalmus. 



to say more than a few words, although they 

 too form a study of great interest to the en- 

 thusiastic naturalist. But the marine zoologist 

 who visits the swamps cannot fail to take note of 

 the millions of Ants, Flies and Mosquitoes which 

 torment him at every step, and make a prolonged 

 stay an impossibility. 



One of the first creatures to be seen on enter- 

 ing a Mangrove-swamp at low tide is a curious 

 little Fish called Periophthalmus. In some places 

 hundreds rnay be seen at one time resting on the 

 roots of the Mangroves, or skipping over the 

 pools of water from one root to another. There 

 are many varieties of Periophthalmus in different! 



