476 DEEP-SEA FISHES OF THE ATLANTIC BASIN. 



monsters of the sea are always represented by those who have had the good fortune of 

 meeting with them as remarkably active, it is not likely that harmless ribbon fishes, which 

 are either dying or dead, have been the objects described as 'sea serpents.'" 



KEY TO THE FAMILIES. 



I. Ventrals well developed 01 absent Trachyptkrip.e 



II. Ventrals reduced to a Bingle Ion;; filament Reualkcii'L 



Family TRACH YPTERID^E. 



Trachypteruke, Swainson, Nat. Hist. Fish., 1839,47. — Gill, American Naturalist, xxiv. 1890. 182. 



Ta^niosomes with the body moderately elongated and very compressed, the head short, 

 the opercular apparatus abbreviated (the operculum extended downwards, the suboper- 

 culum below it, and the interoperculum contracted backwards and bounded behind by the 

 operculum ami suboperculum), ventrals pauciradiate in young, atrophied or lost in adult, 

 the cranium with a myodome ami dichost, the supraoecipital continued behind into a promi- 

 nence, the epiotics confined to the sides and hack of the cranium, and without ribs. 



The ribbon-fishes are well known in the Eastern Atlantic and the Mediterranean, and 

 have even been found as far west as Madeira. Traehypterus has never been found in the 

 Western Atlantic. Some few representatives have been found on the west coast of South 

 America, and one or two examples have been taken in New Zealand. They are generally 

 admitted to be true deep-sea tishes. which live at very great depths, and are only found 

 when floating dead on the surface or washed ashore b\ the waves. Almost nothing is known 

 of their habits except through Nilsson's observations in the far north. This naturalist, as 

 well as Olafsen, 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 their habits resemble those of the "flat- 

 lishes." 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 2 <>r .". 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 ease, however, for the removal 

 of pressure and the rough treatment .by which they were probably washed upon the shore 

 would be demoralizing, to say the least. Trichiurus lepturus,a tish very similar in form. 

 is a very strong, swift swimmer. 



Whether or not the habits of Traehypterus arcticus, on which these observations were 

 made, are a safe guide in regard to the other forms is a matter of some doubt, hut 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 brit- 

 tle, the bones and tin rays exceedingly fragile. 



A considerable number of species have been described, but these are. in most instances, 

 based upon one or two specimens. It is probable that future studies may lie as fruitful as 

 that of Emery, who. by means of a series of 23 specimens, succeeded in uniting at least 

 three of the Mediterranean species, which for half a century or mote had been regarded as 

 distinct. As has been remarked, not a single individual of Traehypterus has ever been 

 found in the Western Atlantic, although the common species of the Eastern Atlantic, T. 

 atlanticus, is not unusually taken, one or more specimens, according to Giinther, being 

 secured along the coast of Northern Europe after almost every severe gale. We have 

 deemed it desirable to include in this paper partial diagnoses and references to the litera- 

 ture concerning each of the species at present recognized in the Atlantic Basin, in order 

 that American naturalists may have at hand a convenient means of identifying material 

 which is almost certain, sooner or later, to fall into their hands. 



We desire to quote the recommendation of Dr. Giinther, and to strongly urge upon 

 anyone who may be so fortunate as to secure one of these fishes that no attempt should 



