32 A HISTORY OF FISHES 



the concave side. Others, hke the Grey Mullet (Mugil), keep 

 the body rigidly in a straight line, so that the course in the air 

 is determined solely by such external factors as the velocity of 

 the wind, the angle of its direction to the fish, and so on. 



The giant Devil-fish {Manta), figuring in so many romances of 

 tropical seas, is another fish which can leave the water on 

 occasion and, by means of an awkward, wheeUng, edgewise 

 leap, sail through the air to a height of more than five feet from 

 the surface of the water. A full-grown specimen is somewhere 

 in the neighbourhood of twenty feet long, and weighs more 

 than 1000 lb., so that its sudden jump from the sea is an awe- 

 inspiring sight. The noise made by its body as it returns to the 

 water resembles the discharge of a cannon, being audible at a 

 distance of several miles. The strength of this fish is prodigious, 

 and when harpooned it will drag a boat through the water at 

 great speed, so that it is sometimes necessary to cut the line 

 at once to avoid disaster. 



The habit of burrowing is generally associated with the eel- 

 like type of body, but some of the Wrasses {Labridae) and the 

 Httle Mud Minnow {Umbra) of North America and Central 

 Europe are adepts at this art. The latter is said to be perfectly 

 at home in the mud, and one author claims that it can "pass 

 through soft mud with as much ease as other fishes do through 

 clear waters." The same writer states that "if suddenly dis- 

 turbed, they generally dart oflf by swimming only, and bury 

 themselves tail foremost in the mud." The method by means 

 of which burrowing is effected is quite simple, the fish merely 

 employing active swimming movements with the snout pointed 

 into the sand or mud. This is continued until a sufficient 

 portion of the body is covered to enable its surface to obtain an 

 effective grip, when progress is more rapid. Bottom-living 

 forms Hke the Rays and Flat-fishes, instead of actually bur- 

 rowing in the sea floor, wriggle their flattened bodies and throw 

 sand over the upper surface until they are completely covered. 





