The sand devil has a flattened, moderately narrow body with greatly enlarged pectoral and pelvic fins. The skin folds along the sides of the head have smooth margins, without lobes. The large eyes are placed on top of the head and have prominent spiracles behind. The nostrils bear thin, pointed barbels with smooth or slightly fringed margins. The wide mouth is positioned terminally on the head. The jaws contain 10 upper and 9 lower tooth rows on each side, with toothless gaps at the middle. Each tooth has a broad base and a single pointed cusp with smooth edges. There are five pairs of gill slits located on the sides of the head.
