The head is broad, triangular and quite distinct from the neck. The tip of the snout is slightly but distinctly upturned. The rostral scale is generally higher than it is wide, touching 2 to 3 scales on the upper side of the snout. Dorsally, the snout is flat with distinct and slightly raised sharp margins. The nasal scale is single (hardly ever divided) and separated from the rostral by a single nasorostral scale. The crown is covered with numerous small and irregular scales of different sizes that are mostly smooth, but sometimes slightly keeled. Frontal and parietal scales are usually not present, but if so, they are small and irregularly shaped, with the frontal separated from the supraoculars by 2 scale rows. The supraocular scales are large and distinct, separated by 4–7 scale rows. There are 10–12 (rarely 8–18) small circumorbital scales below the supraocular. The eye is separated from the supralabials by 2 (rarely 3) scale rows. The vertical diameter of the eye is about the same as the distance between the eye and the mouth. There are 9–13 supralabials. The 4th–5th supralabials (rarely 4th–6th or 5th–6th) are separated from the eye by 2 (rarely 3) rows of small scales, but sometimes there is a single scale between the 4th supralabial and the eye. Generally, the temporal scales are smooth, but sometimes slightly keeled.