'JUMPING JOHXXY.' * 141 



It may easily be imagined what dense and inextricable 

 thickets, what incomparable breakwaters, plants like these — 

 through whose mazes even the light-footed Indian can only 

 penetrate by stepping from root to root — are capable of 

 forming. 



Their influence in promoting the growth of land is very great, 

 and in course of time they advance over the shallow borders of 

 the ocean. Their matted roots stem the flow of the waters, and, 

 retaining the eartliy particles that sink to the bottom between 

 them, gradually raise the level of the soil. As the new formation 

 progresses, thousands of seeds begin to germinate upon its 

 muddy foundation, thousands of cables descend, still farther to 

 consolidate it ; and thus foot by foot, year after year, the man- 

 groves extend their empire and encroach upon the maritime 

 domains. 



The enormous deltas of many tropical rivers partly owe their 

 immense development to the unceasing expansion of these 

 littoral woods ; and their influence should by no means be over- 

 looked by the geologist when describing the ancient and eternal 

 strife between land and ocean. 



When the waters retire from under the tangled arcades 

 of the mangroves, the black mud, which forms the congenial 

 soil of these plants, appears teeming with a boundless variety of 

 life. It absolutely swarms with the lower marine animals, with 

 myriads of holothurias, annelides, sea-urchins, entomostraca, 

 paguri, and crabs, whose often brilliantly coloured carapaces 

 form a strong contrast to the black ooze in which they 

 are seen to crawl about. Life clings even to the roots and 

 branches bathed by the rising floods ; for they are found covered 

 with muscles, barnacles, and oysters, which thus have the 

 appearance of growing upon trees, and pass one-half of their 

 existence under water, the other in the sultry atmosphere of a 

 tropical shore. 



The close-eyed Grudgeon {Periophthalmus), or 'Jumping 

 Johnny,' a^5 he is more familiarly named by the sailors, plays^ 

 a conspicuous part in the animal world of the mangrove 

 swamps, where the uncouth form of this strange amphibious 

 fish may be seen jumping about in the mud like a frog, or 

 sliding awkwardly along on its belly with a gliding motion. 

 By means of its pectoral fins, it is even enabled to climb 



