Front toes webbed; hallux small or absent.
The species are all characterized by short rudimentary wings, bearing four or five barbless shafts, a few inches long, and apparently useless for purposes of flight, of running, or of defence; and by loosely webbed feathers, short on the neck, but of great length on the rump and back, whence they descend over the body forming a thick hair-like covering.
Fuerbringer and Gadow, while others prefer the goose-like voice and the webbed toes as reliable characters.
Some, with the feet only slightly webbed, and the claws exceedingly small or altogether wanting on some of the toes, and also with some difference in dental characters, have been separated as a distinct genus, Aonyx.
It was surprising to see how serenely he sailed off with unruffled breast when he came to the surface, doing all the work with his webbed feet beneath.
