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THE POPULAR SCIENCE MONTHLY. 



As for the gars, I should not mention them in this article, although 

 they are quite peculiar in several respects, were it not for one fact 

 connected with the nature of their skeleton. Their bones are of a 

 green color, a peculiarity which, so far as I am informed, is unique 

 among vertebrates. 



Nor is there anything very peculiar about the flying-fishes, except 

 the excessive development of their pectoral fins, and the habit of 

 " fliglit " connected with this development (Fig. 28). 



Fig. 29. Catfish (SUurus glanU). 



But perhaps we ought not to omit to mention the siluroids (Fig, 

 29), or catfish, for, although they are more like ordinary fishes than 

 some of those already mentioned, their large, broad, and flat head, 

 and large .mouth with its fleshy filaments, give them a decidedly 

 outre appearance, making them quite marked forms in the class of 

 fishes. 



As to the little blind-fishes (Fig. 30), or AmUyopsidce, of the 

 Mammoth Cave, they are very similar in general outline to ordinary 

 fishes, but are peculiar in having the eyes rudimentary and concealed 



Fig. .30. Blind-fish {Airiblyopsis spelmus, 

 Dekay). 



Fig. .51. Lamprey {Petromyzon Amencanin, 

 LeSiieur). 



under the skin, and in having the vent before the base of the pectoral 

 fins at the point indicated by the dotted line in Fig. 30. 



The eels are only or mainly remarkable on account of their elon- 

 gated form. But the lampreys (Fig. 31), though eel-like in form, are 

 not only different from ordinary eels in their structure, but very dif- 

 ferent from all the fishes we have hitherto noticed. Their respiratory 



