Page:Natural History, Fishes.djvu/82

68 and appear to feed at the "bottom, on Loach, Miller's Thumb, and testaceous mollusca."

The scales of the Perch have their hinder, or free edge, set with fine crystalline points, arranged in successive rows, and overlapping. Their

front side is cut with a scolloped pattern, the extremities of undulations of the surface that radiate from a common point behind the centre. These undulations are separated by narrow furrows, across which, contrary to the ordinary rule, the close-set concentric lines that follow the sinuosities of the outline are not visible. Under the microscope they look as if they had been split in these radiating lines, after the whole number of layers had been completed, and that the fissures had then been filled with new transparent substance. The engraving above represents scales selected from different parts of the body of a Perch, and magnified. a is from the back; b is from the lateral line, and shows the tube for the passage of the lubricating mucus well developed; c is from the belly. The concentric lines, it should be observed, are much more delicate and close than could possibly be engraved without greatly enlarging the scale.