Henri Émile Sauvage

“ Most fishes have, beneath the vertebral column, a sort of capsule, which seems to act the part of a floating apparatus. By means of this, the fish can rise in the water or descend at pleasure; it is known as the air-bladder. The sounds emitted by certain fishes, Triglœ, for example, are caused by vibrations communicated to the gases in this organ.
In the protopterus the air-bladder discharges the physiological functions of a lung when the animal can no longer respire through the gills. ”

“ The brilliant colors of the Chœtodons, properly so called, are here wanting; the body is olive-brown or yellow, and bears broad, round, or oblong spots, or vertical stripes of black color; the eye is rose-color and brilliant; the belly, silvery-white.
According to Cuvier and Valencienne, "though the mouth of this fish differs immensely in its organization from that of Chelmon, it, too, can shoot drops of water to a great height, and can hit, with almost unerring aim, insects and other little animals on aquatic plants, or even on the herbage at the water's edge. ”

“ In the beaked Chelmon the body is greenish and iridescent; the fins are green, with reflection of azure; a black spot, surrounded by a pearl-white circle, is seen on the dorsal fin, in length about one-third that of the soft rays; five vertical stripes of azure-color, and bordered with a nacreous white line, adorn the body; one of these stripes crosses the eye obliquely; a second one, bisecting the nape of the neck, extends to the ventral fins; the next two mark the flanks, and the posterior stripe bisects the root of the caudal fin. ”

“ Thus the cocoon is a protecting sheath formed of the mucous secretion. The abundant secretion of mucus, in the first place, coats and strengthens the walls of the burrow made by the protopterus, and hence the subterraneous canal which it had excavated had its sides smooth, and as it were polished. Then, after the animal has reached the required depth, the secretion becomes still more abundant, and the mucus dries, forming a membranaceous envelope of remarkable structure. ”

“ There is another fish that does the same the—mud-fish (Amia) , which is found in the fresh waters of the United States. The Amia, too, is indisputably a fish. There appears to exist some relation between this animal's mode of life and the cellular structure of its air-bladder. Still, the Amia is not an amphibian, in the strict sense of the term. For, though its air-bladder resembles the lung of the serpent, it certainly receives only blood that has previously been aërated; hence we find in this animal no true aërial respiration alternating with strictly aquatic respiration. ”

“ The vertical diameter of the body is very great, and the upright fin of the back is high and scaly; the tail is cut square; the profile, which is concave in front of the eyes, rises almost vertically, so that the snout is about one-fourth the depth of the head. These fishes, known under the name of Chelmons, inhabit the Indian Ocean; naturalists distinguish two species, the beaked Chelmon and the long-beaked Chelmon (see the latter in Fig. 1) . These species differ from each other not only in length of beak, but also in the arrangement of the colors which adorn them. ”

“ The long-beaked Chelmon's body is yellow. Instead of the stripe crossing the eye, seen in the other species, we find on the anterior portion of the body a broad, blackish spot, triangular in shape, and terminating in a point on the snout. This spot is bordered by a nacreous white stripe; the forehead is of azure tint, with a shade of sea-green; the eye is of a pure rose-color; a narrow stripe of black adorns the margin of the fins, which themselves are of mauve-color ”

“ IN the swamps of the Gambia, after they have been dried by the tropical sun, there are to be found here and there beneath the surface clods of earth uniform in shape, and usually about the size of a man's two fists. These clods inclose living animals, which have been led by instinct to hide themselves away toward the close of the rainy season, and before the coming of the season of drought, by burying themselves in the mud while it was yet soft, and before it had been hardened by the scorching rays of the sun. ”

“ On breaking one of these lumps of mud, it is found to be a sort of pouch or cocoon, with thin walls, and with projections here and there corresponding to the form of the animal concealed within. Its larger end is rounded, but its narrower end is closed by a slightly convex lid with a narrow opening in the centre. If the surface of the cocoon be even gently touched, a pretty loud cry is heard which Natterer has compared to the mewing of a cat. ”

“ Each of these gives access to a chamber of moderate capacity, in which are floating certain filamentous appendages. On these are distributed the blood-vessels, which constitute but ill-developed tufts. In water, the animal respires by means of these; when it lives in its burrow, it respires by means of its lung. ”

“ To prevent mixture of the two kinds of blood, that which has respired the oxygen and that which has discharged its physiological function, the auricle becomes divided in two by a partition. The left chamber receives the red blood, just as in the higher animals. ”

“ According to him, the celebrity enjoyed by the archer-fish is undeserved, and rests upon a misapprehension; in short, he shows from the very texts of Pallas and Schlosser that Hommel's observation applies to the long-beaked Chelmon, of which we have spoken above, and that like habits have been gratuitously attributed to the two species, they having been regarded as generically identical.—La Nature. ”

“ Bruguibre, in his "Journal d'Histoire Naturel de Paris," has given it the name of matamata, which is generally accepted by modern zoölogists. The only species from which the genus Chelys has been formed lives in the Guianas ”

“ It feeds on insects, especially such as live on the marine plants which rise above the surface of the sea. In taking them it resorts to a noteworthy manœuvre, which it is enabled to perform by the very elongated form of the snout ”