Page:Popular Science Monthly Volume 27.djvu/415

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THE OLDEST AIR-BREATHERS.
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found abound in Eurypterids, or fossils of a crustacean allied to the king-crab.

Of the recent discovery of earlier Silurian insects, we have the following account given by M. Charles Brongniart to the French Academy of Sciences:

Fig. 3.—Fossil Scorpion, from the upper Silurian rocks of Lesmahagow, Lanarkshire, Scotland, found by Dr. Hunter, Carluke. (Magnified two diameters.)

"Fossil insects have been found in the carboniferous strata. The coal-beds of Commentry have furnished some thirteen hundred specimens, and Mr. Scudder has described six specimens that were found in the Devonian beds of New Brunswick; but, until very recently, no representative of that class had been detected in any of the more ancient formations. M. Douvillé, a professor in the School of Mines, has shown me a piece of Middle Silurian sandstone from Jurques, Calvados, bearing a distinct impression of an insect's wing (Fig. 3). The state of preservation is not perfect, but we can still distinguish most of the nervation. The wing, which is about thirty-five millimetres long, belonged to a blattid, an insect of the cockroach family. The humeral field is broad, and upon it may be seen the superior humeral vein; the inferior humeral vein, bifurcated at its extremity; the vitrean or median vein, likewise divided into

Fig. 3.—Wing of a Fossil Blatta (Palæo-blattina Douvillei). in a piece of Silurian sandstone (natural size). Fig. 4.—Restoration of the Fossil Wing.

two branches; the upper and lower discoidal veins, with their very oblique divisions meeting again at the end, just as they may still be