In Europe a similar species (Trachypterus atlanticus) has long been known by the name of dealfish, or vogmar, neither of these names having any evident propriety.
The dealfish is one of the most singular of all the strange creatures of the sea. It reaches a length of three or four feet. Its body is thin as a knife and would be transparent were it not covered over with a shining white pigment which gives to the animal the luster of burnished silver. On this white surface is a large black blotch or two, but no other colors. The head is something like that of the oarfish, to which animal the dealfish bears a close relationship. Both have small teeth and neither could bite if it would, and neither wants to, for they are creatures of the most inoffensive sort. On the head of the dealfish, where the oarfish has its mane, is a long, streamer-like fin. At the end of the tail, instead of the ordinary caudal fin, is a long, slim fin which projects directly upwards at right angles to the direction of the back-bone. No other fish shows this strange peculiarity.
The dealfish swims in the open sea close to the surface of the water. It does not often come near shore, but it is occasionally blown on the beach by storms. Trachypterus rex-salmonorum has been recorded two or three times from Puget Sound and twice from California. The finest specimen known, the one from which our figure is taken, was secured off the Farallones in 1895 by a fisherman named W. C. Knox, and by him sent to Stanford University. The specimen is perfect in all its parts, a condition rare with these fragile creatures, and its picture gives a good idea of the mysterious king of the salmon.
Fig. 426.—Dealfish, or King of the Salmon, Trachypterus rex-salmonorum Jordan & Gilbert. Family Trachypteridæ. (From a specimen taken off the Farallones.)
Four of these fishes have been obtained on the coast of Japan, and have been described and figured by the present writer in the annals of the Imperial University of Tokyo. These are different from the California species and are named Trachypterus ishikawæ, but they show the same bright silver color and the same streamers on the head and tail. Probably they, too, in Japan are kings of something or other, or perhaps silver swans from the submarine palace, for along such lines the Japanese fancy is more likely to run.
The young of the dealfish has the caudal symmetrical, and the dorsal spines and ventral rays produced in very long streamers.
According to Goode and Bean, the dealfishes are "true deep-sea fishes, which live at very great depths, and are only found when floating dead on the surface or washed ashore by the waves. Almost nothing is known of their habits except through Nilsson's observations in the far north. This naturalist, as well as Olafson, appears to have had the opportunity of observing them in life. They say that they approach the shore at flood-tide on sandy, shelving bottoms, and are often left by the retreating waves. Nilsson's opinion is that its habits resemble those of the flatfishes, and that they move with one side turned obliquely upward, the other toward the ground; and he says that they have been seen on the bottom in two or three fathoms of water, where the fishermen hook them up with the implements employed to raise dead seals, and that they are slow swimmers. This is not necessarily the case, however, for the removal of pressure and the rough treatment by which they were probably washed ashore would be demoralizing, to say the least. Trichiurus, a fish similar in form, is a very strong, swift swimmer, and so is Regalecus. Whether or not the habits of Trachypterus arcticus, on which these observations were made, are a safe guide in regard to the other forms is a matter of some doubt, but it is certain that they live far from the surface, except near the Arctic Circle, and that they only come ashore accidentally. They have never been taken by the deep-sea dredge or trawl-net, and indeed perfect specimens are very rare, the bodies being very soft and brittle, the bones and fin-rays exceedingly fragile. A considerable number of species have been described, but in most instances each was based on one or two specimens. It is probable that future studies may be as fruitful as that of Emery, who, by means of a series of twenty-three specimens, succeeded in uniting at least three of the Mediterranean species which for half a century or more had been regarded as distinct. The common species of the eastern Atlantic, Trachypterus atlanticus, is not rare, one or more specimens, according to Günther, being secured along the coast of northern Europe after almost every severe gale. We desire to quote the recommendation of Dr. Günther, and to strongly urge upon any one who may be so fortunate as to secure one of these fishes that no attempt should be made to keep it entire, but that it should be cut into short lengths and preserved in the strongest spirits, each piece wrapped separately in muslin."
The family of Stylephoridæ is known from a single specimen of the species, Stylephorus chordatus, taken off Cuba in 1790. In this form the tail ends in a long, whip-like appendage, twice as long as the head.
No fossil dealfishes or oarfishes are known.