Page:Popular Science Monthly Volume 11.djvu/554

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

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Fig. 29.—Catfish (Silurus glanis).

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 Amblyopsidæ, of the Mammoth Cave, they are very similar in general outline to ordinary fishes, but are peculiar in having the eyes rudimentary and concealed

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Fig. 30.—Blind-fish (Amblyopsis spelœus, Dekay). Fig. 31.—Lamprey (Petromyzon Americanus, LeSueur).

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 elongated form. But the lampreys (Fig. 31), though eel-like in form, are not only different from ordinary eels in their structure, but very different from all the fishes we have hitherto noticed. Their respiratory