COASTLINES 



Other names given to the mud-skipper are "bommi", 

 'Valking-fish", and "jumping-fish", the scientific name 

 is Periophthalmus — a reference to the fish's prominent 

 eyes, which are set close together somewhat below the 

 line of its profile, and are not only capable of protrusion 

 and retraction, but are furnished with well-developed 

 eyelids. The long body is covered with curious scales; 

 the mouth-cleft is nearly horizontal, with the upper 

 jaw protruding beyond the lower, while the teeth are 

 conical and vertical — all this giving the fish a fatuous 

 yet pugnacious expression. The first dorsal fin has a 

 number of flexible spines, while the breast or pectoral 

 fins are hand-like appendages. With these the creatures 

 walk about over the mud-flats and climb on to the roots 

 of mangrove trees and other forms of vegetation, where 

 they will bask in the sunshine for hours at a time, dang- 

 ling their tails in the water. 



The mud-skipper has an excellent reason for this par- 

 tial submersion of its tail. The tail is freely supplied with 

 blood-vessels, and acts as a second respiratory organ 

 which extracts air from the water — the fish takes in air 

 from both ends. It is a matter of chance whether it 

 breathes through the front end or both, but the fact that 

 it has a habit of tossing itself into the air has nothing to 

 do with this. It may be walking over the surface of the 

 sand, hitching itself along about an inch at every ''step", 

 or ''double step" — when suddenly one of its enemies may 

 appear. It instantly becomes an expert acrobat. It curls 

 its tail to one side and sharply straightens it out with a 

 flick, therefore hurling itself upward and forward to a 

 distance of three or four feet. 



One species, Periophthalmus schlosseri, performs its antics 

 along the shores of the Burmese rivers. At a distance they 

 look like large tadpoles as they rest in the sun, occasion- 

 ally snapping at flies or other passing insects. Suddenly 

 they are startled by something, and off" they go, each 

 making its own hop, skip and jump across the mud, or 



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