Page:Popular Science Monthly Volume 63.djvu/43

Rh, some of the coprolites from early geological horizons which have generally been referred to sharks may have belonged to contemporary lung-fishes. The fecal material at the time it is deposited appears as in Fig. 7a; after remaining in the water for several hours it presents the appearance 7b, and finally, after twenty-four hours, uncoils as in Fig. 7c.

The air-breathing movements of the fish were irregular. At times it would come to the surface about every five minutes and swallow a mouthful of air; then again several times this period would elapse before the fish would rise to the surface. In all cases escaping air passed out through the gill clefts, usually through those on the left side.