The head has a short snout, a little more than twice the length of the diameter of the eye. The crown is covered by small scales rather than large shields, while the scales are usually smooth, feebly imbricate. The first upper labial is not fused to the nasal and is completely separated by a suture. The supraoculars are large, 5-9 scales in a line between them. The internasals are usually not in contact with one another, separated by 2 small suprapostrostral scales. There are 7-10 upper labials, the second of which is usually fused to the scale bordering the facial sensory pit anteriorly. The fourth and fifth upper labials are beneath the eye, but separated from orbit by a series of 2-4 small scales.