312 PLYING REPTILES, FISHES, AND MOLLUSCS. 



branous structure in the mouth, into which air can be 

 drawn through the gills. 



Thus we have in the Flying Fish another instance 

 of the wonderful and yet simple manner in which a 

 slight alteration or development of existing structures 

 enables an animal to adapt itself for a time to a dif- 

 ferent kind of life. 



There is a well-known group of fish called by the 

 popular name of Gurnards, and which have the pectoral 

 fins enlarged or otherwise modified in a most singular 

 manner. Many of them are exceedingly beautiful 

 creatures, the pectoral fins being adorned with spots 

 and stripes of brilliant scarlet, crimson, green, or blue. 

 No idea can be formed of the real beauty of these 

 lovely fishes unless they are seen alive, and this can 

 now be done in the great aquaria which are built in 

 different parts of England. 



Several of these fishes are known as Flying Gur- 

 nards, because, like the Flying Fish, they are able to 

 propel themselves for some distance through the air, 

 upborne on their enormous pectoral fins. Those fins 

 are, however, not long and sharply pointed, like those 

 of the Flying Fish, but they afford the same propor- 

 tionate surface to the air by being rendered very broad 

 and rounded. In them the membrane does not extend 

 quite to the end of the rays, which project like a fringe 

 from the outer top of the wing. 



It is worthy of notice that, in order to increase the 

 width of the fin, and at the same time to give it the 

 necessary strength, the rays are not only very long, 

 but are greatly increased in number. 



