240 THE LI\'ING ANIMALS OF THE WORLD 



The Sea-IK)RSES have a still more eccentricallv- modified form, inasmuch as the body is 

 thrown into a scries of curves, the head being bent upon the trunk in a manner suggestive 

 of the head and neck of the horse; hence the name of the group. The tail, which lacks the 

 membranous portion, or fin, can be spirall}' coiled, and is used as an organ of prehension, 

 and on this account is unique amongst fishes. Gripping the stems of seaweeds with this tail, 

 and swaying the bod}' to and fro among the vegetation, the fish is rendered comparatix'cly incon- 

 spicuous, the lines of the body being broken up by numerous more or less filamentous pro- 

 cesses, which in one species, the FlJCL'S-LlKK Sea-HORSI-;, become excessiveh' developed, forming 

 long, frond-like blades. These, streaming in the water, both by their shape and coloration 

 render the resemblance to the vegetable growths in which the animal hides so perfect that 

 detection is almost impossible. Thus the_\' furnish one of the most remarkable examples of 

 adaptation to the en\ironment amongst li\ing animals. The males of most sea-horses, like the 

 pipe-fishes, carrj' the eggs and \'oung in a pouch on the abdomen, but in the species just 

 mentioned the eggs are embedded in the soft skin on the under surface of the tail. 



Sea-horses swim with the body more or less vertical, the motive power being supplied 

 by rapid vibration of the back-fin. Both pipe-fishes and sea-horses occur in British seas, the 

 first being the more common. 



Photo by H. r. T.eftmamf\ ^'<"' Tork 



COFFER-FISHES 



Coffer-jiihei hafe the body encasej in a hard ihcll oj cloiels fitttng piata^ /eaz'tng only the tall and fim free to mo-ve 



The CoMli-cai.LED Fishes, to which we come next, are tlivideJ into two families, whose 

 members are as remarkable for their extraordinary shape as are the tuft-gilled forms just 

 discussed. The abnormal shapes which mark out certain fishes so conspicuously from the more 

 normal and tvpical forms are generally regarded as adaptations, serving to ensure concealment, 

 to ward oft' attack, or to eft'ect the capture of prey otherwise unattainable. Instances illustrating 

 all three of these ends are furnished b)' these two groups of the tuft- and comb-gilled fishes. 



The FiLE-FlsriES and C<U-'FER-FISHKs, which firm the first of the two families, present 

 considerable variation in shape as well as in the covering of the body, which may be naked, 

 covered with rough scales or bony spines, or invested in a complete bon\' cuirass. 



The file-fishes are represcnteil by numerous species, the tspical one being known also as 

 the TrigcjER-fisii, on account of an armature of spines on the top of the bade. These spines 

 are three in number; the first is very strong, roughened like a file — hence the name File- 

 fish — and hollowed out behind to recei\-e the second much smaller spine, which has a 

 projection in front at its base, fitting into a notch in the first. Thus these two spines can 

 only be raised or ciepressed simultaneously, and the first cannot be forced down unless the 

 second has been previoush- depressed. These fishes have very powerful teeth, to break off 

 pieces of coral, which form a large part of their diet. They also destro}' a large number of 

 shell-fish, and work great destruction amongst pearl-oysters. Frequently these fishes, when 

 eaten, prove highly poisonous, from ha\-ing fed on poisonous corals, jelly-fish, or decomposing 

 substances. 



