The first observations on the feeding habit of Amblyopsis are those of Cope. He remarks that “the projecting lower jaw and upward direction of the mouth render it easy for the fish to feed at the surface of the water, where it must obtain much of its food.... This structure also probably explains the facts of its being the sole representative of the fishes in subterranean waters. No doubt many other forms were carried into the caverns since the waters first found their way there, but most of them were like those of our present rivers--deep-water or bottom feeders. Such fishes would starve in a cave river, where much of the food is carried to them on the surface of the stream.” [Illustration: FIG. 8.--_Aphyonus gelatinosus_, 1,400 fathoms, between Australia and New Guinea. FIG. 9.--_Aphyonus mollis_, 955 fathoms, 24° 36′ north, 84° 5′ west. FIG. 10.--_Tauredophidium hextii_, 1,310 fathoms, Bay of Bengal. FIG. 11.--_Acanthonus armatus_, 1,050 fathoms, mid Pacific, off the Philippines. FIG. 12.--_Typhlonus nasus_, 2,150 to 2,440 fathoms, north of Australia and north of Celebes. FIG. 13.--_Hephthacara simum_, 902 fathoms, Coromandel coast. FIG. 14.--_Alexeterion parfaiti_, 5,005 metres, North Atlantic.] The observations of Cope are entirely erroneous, as we shall see, and the speculations based on them naturally fall to the ground. Dr. Sloan recorded one Amblyopsis which he kept twenty months without food. “Some of them would strike eagerly at any small body thrown in the water near them, rarely missed it, and in a very short time ejected it from their mouths with considerable force. I tried to feed them often with bits of meat and fish-worms, but they retained nothing. On one occasion I missed a small one, and found his tail projecting from the mouth of a larger one.” Wyman found a small-eyed fish in the stomach of an Amblyopsis. Hoppin was struck by the fact that, if not capable of long fasts, Troglichthys must live on very small organisms that the unaided eye can not discern. Garman found, in the stomachs of Troglichthys collected by Hoppin in Missouri, species of Asellus, Cambarus, Ceuthophilus, and Crangonyx.