Page:Natural History, Fishes.djvu/300

286 of the body so abrupt, that the observer is apt to imagine that he looks upon the anterior half of a fish, cut across through its middle. These are fishes of gigantic size, which are sometimes taken in the British seas.

About a hundred species are enumerated as belonging to the Family, the great majority of which are confined to the warm parts of the ocean. All are, we believe, marine in their habits.

A depressed line, passing down the front of the aggregated teeth in both jaws, gives to the fishes of this genus the appearance of possessing four great teeth, two above and two below, whence the generic appellation. The body, either wholly or at least on the under partsunderparts [sic], is studded with prickles, varying in size and in number. In some species, indeed, these are so small and so imbeddedembedded [sic] in the soft mucous skin, as not to be perceptible in a living state, but drying or preservation in spirit reveals them.

“The species of this genus,” observes Dr. Roget, “are remarkable for being provided with the means of suddenly assuming a globular form by swallowing air, which passing into the crop or first stomach, blows up the whole animal like a balloon. The abdominal region being thus rendered the lightest, the body turns over, the stomach being the uppermost part, and the fish floats upon its back, without having the power of directing itself during the state of forced distension. But it is while thus bloated and