Sword Fish, the name of the xlphiidoe, a family of marine spiny-rayed fishes, allied to the mackerels, so called from the prolongation of the snout into a long, horizontally flattened, sword-like weapon. The sword consists of the vomer and intermaxillary bones, supported at the base by the frontals, nasal, and upper jaw. In form this fish resembles the mackerel; the scales are very small; the jaws proper, and sometimes the sword, are crowded with small, acute teeth, often hardly perceptible; the lam-inaa of each branchial arch are united into a band-like organ, with only superficial marks of separation, as in no other bony fishes; branchi-ostegal rays in the typical genus xiphias (Linn.) seven. The spinous dorsal begins near the head, high and sickle-shaped, extending nearly to the tail, and followed by a small soft fin; the anal is similar, but much shorter; ventrals wanting, or represented only by a pair of spinous rays on the throat; caudal deeply forked, on the sides having one or two large cutaneous folds; the pyloric appendages are collected into bundles and connected by areolar tissue, the branches forming two trunks inserted into the intestine close to the pylorus; the stomach caecal and conical, and the air bladder large; the lower jaw in the young is proportionally longer than in the adult; the sclerotic forms a bony box, with a circular opening in the front for the cornea, rendering the eyes very movable.

They are very swift swimmers, and feed on mackerel and other fishes collecting in shoals. The common sword fish (X. gladius, Linn.) attains a length of 12 to 20 ft,, and is found in the Mediterranean and on both sides of the Atlantic; it uses its sword to destroy its enemies, and sometimes strikes at vessels, burying its weapon deep in their timbers. There are no ventral fins, and the sword is about three tenths as long as the body. It occurs on the North American coast from Nova Scotia to New York, being common in the summer in Vineyard sound and between No Man's Land and Block island; it is silvery white below, and tinged above with blackish blue, the sword dark brown above and lighter below. It is fond of pursuing the shoals of mackerel, and may be detected by the dorsal fin projecting above the water. They are taken by means of harpoons. The flesh is esteemed as food, both fresh and salted.

Common Sword Fish (Xiphias gladius).

Common Sword Fish (Xiphias gladius).