BALISTES, in natural history, a genus of Branchiostegous fishes. The generic characters are : teeth eight in each jaw, of which the two anterior ones are longer, and three lateral ones on each side more obtuse ; body compressed ; abdomen carinated ; skin tough, often reticulated by scale-like divisions. There are 24 species ; of which we shall mention the following, viz. the B. monoceros, or uni corn file-fish, which is often two feet long or more ; the body is of an oval shape, and possesses the power of inflating at pleasure the sides of the abdomen, by means of a pair of bony processes within that part ; the skin is every where cover ed with minute spines, and the general colour is grey, inclining to brown on the upper parts, and varied with irregular, dusky, subtransverse undulations and spots : immediately over the head, just above their eyes, is a strong, single, re. curved spine, of considerable length, and serrated on the hind part : both fins and tail are of a pale brown colour, the latter being marked by a few dusky bars. This fish is a native of the Indian and Ameri can seas, feeding chiefly on crustaceous and testaceous marine animals. It is said to be a poisonous fish. B. vetula, or an cient file-fish, is likewise denominated the old wife fish, a name which it is sup posed to have obtained from the appear ance of the mouth when viewed in front, as well as from the slightly murmuring noise which it utters when first taken. B.
maculatus, spotted file-fish, is of an oval shape ; its length is about eighteen or twenty inches, sometimes as much as two feet ; colour pale violet; skin strongly marked into lozenge-shaped reticulations; first dorsal fin three-rayed; the first very strong; ventral spines rough, and but slightly projecting ; tail somewhat con vex in the middle of the outline, with falcated tops ; whole body dorsal, and anal fin marked with numerous round blue spots. Native of the Indian and American seas. B. undulatus, or black file-fish, is a native of the Indian seas, ob served first about the shores of Sumatra by the enterprizing and highly merito rious traveller Mungo Park. From the mouth to the base of the pectoral fins run three red lines, and the body is ob liquely undulated by twelve lines of the same colour. Some fish of this genus are, called Trigger-fish, from the circum stance of the first ray of the dorsal fin be ing fixed by the second, when elevated to a perpendicular position, like the trigger of a gun; this ray cannot be restored to its oblique position without first inclining the second ray, which by a peculiar me chanism, acts as a prop. See Plate II. Pisces, fig. I.