In the middle part of the body there are 19 (rarely 17 or 21) rows of dorsal scales. In contrast with many other snakes found in the region, these scales are flat (not keeled). This gives the snake a smooth texture to the touch, from which it gets its common name. The ventral scales number 150-164 in males and 162–200 in females. The anal scale is divided (rarely single) and the subcaudal scales are paired. Males have 54–70 subcaudal scales and females 40–76.