The Air-Bladder of Fishes.—While engaged in measuring a degree of the meridian in 1806, the eminent physicist and astronomer Biot accidentally made the discovery that fishes living at great depths have the air-bladder filled with almost pure oxygen. Another French scientist, Dr. Moreau, has recently confirmed and extended this observation of Biot's. According to Moreau, the air-bladder secretes pure oxygen, and the presence of other gases is due to other causes besides the secretion of the organ. To prove this point, he examined fishes which had for a considerable time lived in very shallow water, and found, from several analyses, that the average amount of oxygen in the air of their swimming-bladders was about sixteen per cent. He then plunged the fishes in water to the depth of about twenty-five feet, and found that the quantity of gas in the air-bladder was increased. The oxygen was now from forty-five to fifty-two per cent.
New Fossil Ungulates from Mexico.—In a communication to the Philadelphia Academy of Natural Sciences, Prof. Cope describes some new fossil Ungulata found by himself while employed in the Wheeler Topographical and Geological Survey of New Mexico. One of these fossil ungulates, Pliauchenia Humphreysiana (a new genus and species), is regarded as representing a genus of Camelidæ intermediary between Procamelus occidentalis and Auchenia. P. Humphreysiana was of about the same size as the former of these two animals, or somewhat larger than any of the existing llamas. Another new species of this same genus is Pliauchenia vulcanorum, represented in Prof. Cope's collection by the left maxillary bone, which proves it to have been a camel of about the size of the existing dromedary, and considerably larger than the preceding species. The typical specimen was found near Pojuaque, a village of the Pueblo Indians. Various bones of camels of the size of P. vulcanorum were also found, some of which doubtless belong to the same species. Of Hippotherium calamarium, a new species of three-toed horse, the oral and palatine parts of the skull, with the superior dental series of both sides, were found near San Ildefonso. Dr. Cope points out the specific differences between this animal and Leidy's H. occidentale, H. speciosum, and H. gratum. Aphelops jemezanus, a new species of fossil rhinoceros, is represented by a right mandibular ramus, found near the town of Santa Clara, on the west side of the Rio Grande.
Parental Instinct in Fishes.—The Trinidad perch does not stand all alone among the finny tribes in caring for the safety of its young. A correspondent, after reading the article "A Motherly Fish," on page 126 of the present volume, writes us as follows: "I think it is known to our fishermen that the catfish watches over its young. For the fact that it does I can vouch. A friend whose place of business was on the quiet wharf of Havre de Grace, Maryland, had an opportunity, during more than a week and several times each day, of observing the parental care of this fish. There were always two fishes with the brood. When approached, one of these would dart off, while the other, naturally supposed to be the mother, could be seen to flap her tail against the bottom till a cloud of mud was raised, concealing herself and her little ones. When the observer remained perfectly still for some time, the water becoming clear again, the mother could be seen hovering over a dark mass of moving small-fry a foot or more in diameter, while a little way off the other fish would be in attendance."
Mouthless Fishes. Prof. Leidy lately exhibited at the Philadelphia Academy of Sciences an apparently mouthless fish, found in the Ouachita River, Arkansas. The fish is the buffalo sucker (Catastomus bubalus) an inhabitant of the Mississippi and its tributaries. The specimen is fifteen inches long. The maxillaries, premaxillaries, and mandible, are absent, and the integument is tightly extended between the end of the snout, the suborbitals, and the articular ends of the quadrates. In the centre of this expansion of the skin there is a small oval aperture one-fourth of an inch fore and aft, and one-eighth of an inch in transverse diameter. The hole is sufficient to admit a current of water for the purposes of respiration; but it is difficult to understand how the fish had procured its food. The cyprinoids generally are remarkable for
