2598 Bulletin 4.7, United States National Museum. 



separate, free from the isthmus ; gills 4, a slit behind the fourth. Pseudo- 

 branchiae well-developed, in a pouch formed by a fold of the mucous 

 membrane. Dorsal fin single, extending from the head to the tail, its 

 rays all technically spinous, being neither articulated nor branched, but 

 all very soft, flexible, and fragile; anal fin wanting; pectorals short; 

 ventrals thoracic, the rays elongate, less than I, 5 in number, usually 

 atrophied in the adult ; caudal fin either rudimentary or else divided into 

 2 parts, the upper and larger fan-shaped, directed obliquely upward from 

 the slender tip of the tail. Bones very soft, the muscles little coherent. 

 Pyloric cca very numerous. Vertebra* in large number. Deep-sea fishes, 

 often of large size, found in most warm seas. Their extreme fragility ren- 

 ders them rare in collections, and the species are little known. One 

 genus; species about 12. The ribbon-fishes are well known in the East- 

 ern Atlantic and the Mediterranean, and have even been found as far 

 west as Madeira [and Cuba]. Some few representatives have been 

 found on the west coast of South America, and 1 or 2 examples have been 

 taken in New Zealand. They are generally admitted to be 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 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 its habits resemble those of 

 the flat fishes, 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 or 3 fathoms of water, where the fisherman 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 

 upon the shore would be demoralizing, to say the least. Trichiurus, a fish 

 similar in form, is a very strong, swift swimmer, and so is Reyalecus. 

 Whether or not the habits of Trachypterus arcticus, on which these obser- 

 vations were made, are a safe guide in regard to the other forms is a mat- 

 ter 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 acciden- 

 tally. They have never been taken by the deep-sea dredge or trawlnet, 

 and, indeed, perfect specimens are very rare, the bodies being very soft and 

 brittle, the bones and fin rays exceedingly fragile. A considerable num- 

 ber of species have been described, but in most instances each was based 

 upon 1 or 2 specimens. It is probable that future studies may be as fruit- 

 ful as that of Emery, who, by means of a series of 23 specimens, succeeded 

 in uniting at least 3 of the Mediterranean species, which for half a cen- 

 tury or more had been regarded as distinct. The common species of the 

 Eastern Atlantic, Trachypterus atlaniicus, is not rare, 1 or more specimens, 

 according to Giinther, being secured along the coast of northern Europe 

 after almost every severe gale. We desire to quote the recommendation 

 of Dr. Giinther, and to strongly urge upon any one who may be so fortu- 



