Page:Natural History, Fishes.djvu/224

210 bones are set with stout teeth, forming, as it were, a pair of jaws at the entrance of the gullet; these are opposed by a great flattened disk of stony hardness, placed above them, and lodged in a cavity or socket in the base of the skull. Between these, the vegetable substances on which these fishes principally subsist, are strongly ground down, before they are transmitted to the stomach; and thus compensation is given for the entire absence of teeth in their more ordinary situation at the anterior orifice of the mouth.

The scales in the Carps have their free margins rounded and entire, and their front, by which they are imbedded into the skin, cut into sinuosities, but not toothed. The accompanying engraving represents scales selected from various parts of the Gold-fish, (Cyprinus auratus, ) Figs. a, b, and c, are scales from the lateral line, the first taken just behind the head, the second in the middle, and the third near the tail. The lower part in the figures is the free portion, which alone is visible in the fish, the other part being concealed by the three neighbouring scales that overlap it, above, in front, and below. The tube before referred to, (see page 7), is seen to pervade each, running through a portion of it longitudinally, so that it opens posteriorly on the outer surface, and anteriorly on the inner or under surface of the scale. In the scales near the front of the line, the tube is large and prominent, (as in a,) while, in the very last scale at the opposite extremity, it is merely a groove. d, is a scale from the back; e, one from the middle of the belly, and f, one from the throat. The variety of form in the scales is illustrated by these figures, which