PORCUPINE-FISH. One of a family, Dio dontidfc, of the order Plectognathi, allied to the globe-tishes, from which they differ chiefly in the stronger armature of the skin, and in having no division in the bony plate of either jaw. They are short and broad in form, and are covered everywhere with splices, each rooted upon a bony base, and in some species with strong. hair-like bristles. Each jaw is covered with a bony plate, like a beak of a bird, and the nostrils form small tentacles. They are sluggish fishes, inhabiting warm seas of various parts of the world and living on the bottom among weeds and corals. When disturbed they swallow air. and float belly upward on the water. but their capacity of inflation is much less than that of the globe-fishes. They are generally regarded as poisonous, and therefore rarely used as food, but they are often utilized as curiosities. The best
known species is Diodon hystrix, common every where in the tropics, and often taken in Florida, where its Spanish name is 'erizo.' (See Plate of PLECTOGNATII FISHES.) It reaches a length of about three feet. Another smaller and darker species of these fish is Diodon holacanthus, also well known. An allied species, Chylumyrterus Sehoepfi, only six to ten inches long, and very abundant in the bays and lagoons from Virginia to Florida, swells up when touched after the manlier of the Northern puffers. It is greenish in color, with the abdomen paler. the back and sides marked by round black spots and parallel black stripes. Its common names are 'burr-fish,' 'rabbit-fish,' and 'swelled toad.' Several other species of the same genus exist in the tropics.