MUD-SKIPPERS — INSE CTS 



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mangrove-roots are washed by the sea at high tide. One Malay species, 

 P. phya, is noteworthy from the circumstance that it constructs a more 

 or less permanent burrow, in which it takes refuge when alarmed, and where 

 it remains in seclusion during bad weather. This burrow, which is frequented, 

 apparently, by both sexes, may be employed as a nursery, although this point 

 is not definitely ascertained. The larger burrows, which have funnel-shaped 

 entrances, are always situated in pools of water between tide-marks ; the water being 

 retained in the pools by means of walls of mud from four to six inches in height 

 and with a diameter of about eighteen inches, these being constructed by the fishes 

 themselves. Outside the walls are a number of small holes, which may or may 

 not lead into the central burrow and are employed as retreats on ordinary 

 occasions. When, however, the fish are thoroughly alarmed they skip on to the 



koelreuter's mud-skipper. 



walls, where they sit for a time before diving into the pools and seeking safe 

 refuge in one of the large burrows, which always run in an oblique direction. 

 According to native reports, these fishes obtain the mud or clay of which the walls 

 are built by diving to the bottom of the pool and bringing up a mouthful at a time ; 

 this being confirmed by the appearance of the wall itself, which is formed of 

 pellets of clay differing in character from the surrounding surface-mud, and of 

 such a size and shape that they might well be casts of the fish's mouth. 



The commonest and most widely spread species is P. koelreuteri, which ranges 

 from the Red Sea to the Pacific islands, and measures about six inches in length. 

 A member of the group inhabits the West African coast in the neighbourhood of 

 the Niger ; but these fishes are unknown on the opposite American coast. 



In addition to the numerous species to be met with on the shore, 

 there are certain kinds of insects which actually live on the surface 

 of the open sea, miles away from land ; these being the so-called sea-flies or sea- 



insects. 



