LANTERN-FISH. A name given to soft rayed, pelagic fishes, of a provisional order, Ini omi. in reference to the fact that most of them possess phosphorescent, luminous organs, required by their residence in the dark oceanic abysses. Their general structure is that of iso spondylous fishes, which have become degraded or degenerate by an unfavorable environment. Their forms are often most unusual and grotesque, great heads with enormous eyes and large mouths, often studded with formidable teeth, being united with slender and fragile bodies. The bones are weakly ossified, the mesacoracoid is lacking (an eel-like characteristic), and the con nection of the shoulder-girdle with the cranium is imperfect. Ichthyologists differ as to whether or not the group should be separated from the Isospondyli; and also whether its component parts should be regarded as families or as gen era. Jordan and Evermann take the former view, and make the first family that of the lizard-fishes including a group of tropical predaceous fishes inhabiting sandy bottoms not far from shore. often brightly col ored and lizard-like in form, whence the common name `lagarto' in Spanish America. (See LIZARD FISH.) The other families are almost all inhabi tants of the abysses, and the species are largely known only by one or a few specimens. The species illustrated upon the accompanying plate are representative ut the range of variety in the group. Thus Bathyptcrois quadri/ilis, remark able for the four long, whitish tit:intents of its fins (tactile organs of extreme sensibility), is a little fish. nearly black, and dwells in the tropical Atlantic at a depth of 500 to 800 fathoms. Another small, dark-colored bottom
fish (live and one-half inches) is limops Murrayi, found widely distributed at a depth of about 2000 fathoms, which is provided with an extraor dinary sensory apparatus. It is eyeless, but the whole top of the flattened head consists of a pair of large, transparent membrane-bones. which cover a peculiar divided organ, one-half lying on each side of the median line of the head. This at first was supposed to be a luminous organ, but. closely has discovered that it represents the lost eyes. each half of the organ having a flat tened cornea along the dividing line, and a large retina of complicated structure, adapted to pro duce an image and to receive especial luminous rays. Referring especially to this fish, Alexander Agassiz has stated that while in some cases the eyes of these migrants from the shores and the surface to the black depths have not been spe cially modified, in others there have been modi fications of a luminous mucous membrane. lead ing on the one hand to phosphorescent organs more or less specialized. or on the other to such remarkable structures as the eyes of :poops, intermediate between true eyes and specialized phosphorescent plates. Where the fishes have be come Idind, the integument. lifteral line. and various tactile appendages aequire extraordinary sensibility, as in cave animals (q.v.). The curious miniature of a whale illustrated in Fig. 0 of the Plate is one of the two known spe cies of the genus retonlimus, less than six inches and living at great depths. For an account of Fig. S. see LANCET-FISIL