228 THE LIVING ANIMALS OF THE WORLD 



Venomous Snakes. The poison-wea'pons are a spine on the gill-cover and two spines of the 

 back-fin. The former is of the same shape as the hollow venom-fang of a snake, perforated 

 at both ends. A little bag containing the poison lies at the base <jf the spine, and when 

 pressed by the spine as it makes its puncture ejects its contents into the body of the latter, 

 whence it escapes from the hole in the top. The structure of the back-spines is similar. 



The family of the Angler-FISHES contain more strange forms than any other. Living 

 on the sea-bottom and seeking their prey by stealth, angler-fishes do not need powerful 

 swimming-muscles; consequently the size of the body and tail has become considerably 

 reduced, so that the head, relatively to the rest of the body, is unusually large. The head, 

 jaws, and bell\' are indeed of great size and capacity. The side or paired fins are not 

 used for swimming, but have become modified to serve as feet, enabling the fish to shuffle 

 along the ground. A further remarkable feature of these fishes is seen in the back-fin, 

 the rays of which arc very long, the foremost being provided with a flag-like flap of skin at 



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ANGLER-FISH 



TAis hideous spciUs is also called the Frog-fish 



the top, e.vtremely sensitive to touch, and pla\'ing a vcr_\' important part in the capture of 

 food. It seems that the fish commonly lies concealed on the sea-bottom, with this " flag " 

 erected. From its general resemblance to the surrounding seaweed it is quite inconspicuous, 

 so that passing fishes take no trouble to avoid it. If by any chance they should touch it, 

 however, the jaws beneath open instantly, and the unfortunate trespasser is suddenly engulfed. 

 This elaborate and sensitive mechanism has been likened to a spring-trap, which is always set, 

 and never betrays its presence. It seems probable, however, that this flag serves also as a lure, 

 passing fishes being occasionally attracted by the waving flap of skin. Should they become 

 sufficiently curious as to proceed to touch it, capture in the manner above described is certain. 

 Certain deep-sea forms have a luminous organ in the place of the flap of skin, and this 

 certainly seems to act only as a lure. 



Angler-fishes are found all over the world; some, as we have seen, are bottom-fishes, some 

 inhabit deep sea, whilst others lie hidden amongst floating seaweed, to which they cling by 



