LEPIDOSI'EEN (or protop(erus), a very remarkable genus of animals, one of the con necting links between amphihia (or batraehia) and fishes, and ranked by some naturalists with the former, and by some with the latter. Owen strenuously maintains the proper place of this genus to be among fishes. There are several species of lepidosiren. of which the best known is L. annectans, an inhabitant of the upper part of the river Gambia. It is about a foot long. The bones are very soft and cartilaginous, or even gelatinous, except thoiie of the head, which resemble in substance those of osseous fishes. The scales are cycloid. The dentition is very remarkable. The jaws are furnished with an undulating ribbon of bone, covered with enamel, the undulations of the upper and lower jaw adapted to each other, and along the edges are smalt sliarp teeth. Timm are free filamentary gills situated under gill covers, as in osseous fishes. but two of the arterial arches, which ordinarily supply the gills of fishes with blood, are represented in lepi dosiren by trunks. which proceed to the double air-bladder, and ramify over its cellular surface, so that the air-bladder, having a communication with the mouth, is capable of serving to a certain extent the purposes of lungs, and the animal is enabled to sustain a torpid existence during the dry season in mud, in which it forms for itself a kind of nest, which has been likened to the cocoon of an insect, by means of a mucous secretion from its body. Specimens of I, annectans have sometimes been brought from Africa
with plants. among the roots of which they have taken up their residence. Numerous specimens have been kept alive in the zoological gardens of London and the Crystal Palace. and their habits hive been carefully studied. They do not seem to need the annual period of torpidity, for which, :is forced upon them in their native country, they arc so Well prepared. They readily eat any kind of animal food; frogs are particularly acceptable; and when placed in the same tank with goldfishes, they kill them by a single bite close to the pectoral fins, approaching them flop' below, biting out the piece, and often eating no more of the fish than that one bite. In its native country, the flesh of the lepidosiren is much esteemed.
LEPIDOSTE1DiE, a family of fishes which are the only living representatives of the order rhomboganoidea. They have an elongated, nearly cylindrical body, covered with rhomboidal scales. The head terminates in a long, beak-like snout, with nostrils near the end of the upper jaw, which is longer than the lower. The dorsal fin is set well back and above the anal fin. They include the genus lepidosteus, to which the gar and alligator gar-fish of the North American lakes and rivers belong. They somewhat resemble the true gar-fishes in appearance. See GArt-Fisn, ante.