In a large specimen which I examined, the skin was covered with a remarkable mucilaginous envelope, in which were numerous parasites; while in the mouth was a large goose-barnacle, which was situated just far enough in to escape being crushed by the formidable teeth. If asked to select a fish showing evidences of possible phosphorescence, I should name the sunfish, as the curious envelope of mucus seems particularly adapted as the seat of this remarkable phenomenon; but I have not only never observed its luminosity, but have been unable to obtain a direct statement from any one in this country as to its light-emitting quality. I give it a place among the luminous fishes, on the authority of T. Spencer Cobbold, M.D., F.L.S., who says, in referring to it, “It is nearly circular in form; and the silvery whiteness of the sides, together with their brilliant phosphorescence during the night, has obtained for it, very generally, the appellation of sun or moon fish.” Karl Semper, in his “Animal Life,” says: “The fishermen of Nice assert that the moonfish (_Orthagoriscus mola_) is luminous;” but as no scientist, that I am aware of, makes a definite statement of personally observing its light, we will leave the moon or sun fish among the forms which are possibly phosphorescent, yet not proven so. Statements are often made regarding the phosphorescence of whales and other cetaceans; but the wondrous displays which they undoubtedly produce as they rise, perhaps to escape the ferocious attacks of the killer, are due only to the myriads of small light-givers,--_medusæ_, _salpæ_, crustaceans, and others,--which when disturbed become luminous. Among the well-known phosphorescent fishes, the _Scopelus_, found in the greater depths, rises at times, at night, to the surface. _Scopelus humboldtii_ (Plate X., Fig. 1), has a double row of luminous spots on each side of the abdomen. One of the spots, enlarged in reflected light, is shown in the same plate. The phosphorescence of _Myctophum crenulare_, an ally of _Scopelus_, has been observed; and, at least on the Pacific coast, this little fish probably rises to the surface, a specimen an inch and a half in length having been taken from the stomach of an albicore (_Orcynus alalonga_) in the Santa Barbara Channel. In this specimen a phosphorescent spot was seen on each mandible near the symphysis, thirty-three along the abdomen, six in front of the ventral fins, six more between the latter and the origin of the anal, and twenty-one between the front of the anal fin and the base of the tail; quite enough, if all are luminous, to outline the little creature in lines of vivid brightness.