THE PADDLEFISHES Family I. Polyodontidae Body fusiform, scarcely compressed; skin smooth, scaleless; snout lengthened and expanded into a long, thin, flat blade or spatula, the inner part formed by the produced nasal bones, the outer portion with a reticulate bony framework, the whole somewhat flexible; mouth broad and terminal, but overhung by the broad spatulate snout; border of mouth formed by the premaxillaries, the maxillaries being obsolete; jaws and palatines with numerous fine, decidous teeth in the young, scarcely evident in the adult; no tongue; spiracles present; opercle rudimentary, its skin produced behind in a long, pointed flap; no pseudobranchiae; gills 4 1/2; gillrakers long, in a double series on each arch, the series divided by a broad membrane; gill-membranes connected, but free from the isthmus; a single broad branchiostegal ray; no barbels; nostrils at the base of the blade and double; a well-developed and continuous lateral line, its lower margin with short branches; dorsal fin placed posteriorly, of soft rays only; anal fin similar, somewhat more posterior; tail heterocercal, the lower lobe, however, well-developed, the tail being thus nearly equally forked; sides of the upper caudal lobe armed with small, rhombic plates; pectoral fins moderate, placed low; ventrals many-rayed, abdominal; air-bladder cellular, not bifid; pyloric coeca a short, broad, branching, leaf-like organ; intestine with a spiral valve; skeleton chiefly cartilaginous. This family contains but two known species--Psephurus gladius, a singular inhabitant of the fresh waters of China, and the paddlefish found in the United States.