volume of waters making this giant river flow until they reach the Atlantic. The sea-water 

 barrier cannot halt their course and in the open sea more than 10 miles from the great delta 

 the fresh waters of the Amazon are still to be found at the surface. 



The swamps of Asia. 



The moisture-laden air lies oppressively over the lower plains with their gently rustling 

 bamboos. It overlies rice-fields, the deltas of great rivers and the stagnant waters of marshes 

 that are hidden under a treacherous carpet of water-plants. The potent scent of vegetation 

 rises in the heat and the odours of a swarming life are mixed with the unpleasant smell of decay. 

 In the dense shade of the great trees there is no breath of wind. The fierce, dazzling rays of 

 the sun stream into the dried-up clearings where the mud cracks into hexagonal patterns. Both 

 brackish and fresh waters are rank, and for a long time any trace of life-giving oxygen has been 

 wanting. The boundaries of banks become indefinite, for among the plants the muddy water- 

 sides merge into the mire of the swamps. 



Tired with swimming in these overpowering surroundings, the fishes slither over the bottom, 

 where they find some food. Then lleeing from the stench of the polluted waters, they rise 

 towards the sun and the pure air. Some species have become eel-like. Wriggling along, they 

 emerge from the disturbed depths of pools to shelter under the moisture-laden leaves of reeds. 

 The cuchia (Amphipnoiis ciichia) has assumed the form of a snake, the pectoral and pelvic 

 fins having disappeared, while the unpaired dorsal and anal fins are reduced to mere feeble folds 

 of skin. This symbranchid fish leads an amphibious life. When it is in the water it often 

 rises to the surface to gulp in air but it does not stay there long and is often found lying on 

 the banks. 



Another eel-like fish Rhynclwbdella, of the family Mastacembalidae, has appendages at 

 the end of the snout that enable it to burrow in the mud. It is claimed that this animal is 

 so well adapted to an aerial life that it " drowns " if unable to breath atmospheric air. The 

 anabantid fishes (Anabas scandens, A. icsfiidineiis) have the standard fish shape and they 

 belong to a family related to grey mullets. However, they can travel out of water with a 

 surprising speed, which has led to the popular name " mouse ". Their gill complex consists 

 of a cavity filled with elaborate lamellae, which enable them to store a small amount of water. 

 Guarded against the rigours of a long stay out of water, they travel over land by heeling over 

 and using their gill-cover spines as crampons. The scales along the tail-stalk are very spiny, 

 thus affording them extra purchase. By this method of creeping they can cover long distances. 

 The snake-heads (Ophiocephalus slriatus), which are related to the anabantids, have a more 

 elongated body, edged above and below by long fins. They have labyrinthine respiratory- 

 organs. They seek out the moisture-saturated plants along the banks but also remain for a 

 long time in the foul and overheated waters of the swamps in conditions that other animals 

 could not tolerate. A snake-head from Ceylon, Channa, has become eel-like and leads much 

 the same kind of life as the cuchias. 



In the brackish waters of the great deltas of the Mekong and the Irrawaddy, and going up 

 into marshy waters, there is a goby called Periophthalmiis. It hops along the clinging-roots 

 of mangroves or perches itself, while supported on the fork between the pectoral fins, on a stone 

 in the full glare of the sun. With its head raised, it ceaselessly scans its immediate surroundings 

 with its bulging mobile eyes. When the gills become dry from the intense heat it trails its 

 tail in the water and is able to respire through the very thin skin. 



Near the river banks in the East Indies, the archer-fish, Toxotes jaciilalor, lives among the 

 reeds. It is well known for the way in which it catches flies. When one of these insects hovers 

 near the surface, the fish shoots out of its mouth a large drop of water, even when its prey is 

 a fair distance (sometimes more than three feet) away. The drop rarely misses its mark and 

 the shot-down fly is immediately swallowed. 



140 



